COMET® Review of Aeronautical Meteorology Distance Learning Course

Description:
In order to help forecasters build a strategy for anticipating convective storm structures, their evolution, and the potential for severe weather, A Convective Storm Matrix provides learners the opportunity for extensive exploration of the relationship between a storm's environment and its structure.

The matrix is composed of 54 four-dimensional numerical simulations based on the interactions of 16 different hodographs and 4 thermodynamic profiles. By comparing animated displays of these simulations, learners are able to discern the influences of varying buoyancy and vertical wind shear profiles on storm structure and evolution.

A series of questions guides the exploration and helps to reveal key storm/environment relationships evident in the matrix. A synopsis of the physical processes that control storm structure, as well as the current conceptual models of key convective storms types, is included for reference.

Subject matter expects for A Convective Storm Matrix: Buoyancy/Shear Dependencies include Mr. Steve Keighton, Mr. Ed Szoke, and Dr. Morris Weisman.

Note: This module was originally published on CD-ROM in March 1996 (v1.1) and re-released in 2001 as v1.3 for Microsoft Windows users only. CD-ROM version 1.3 works fairly well with Windows 98/ME/NT4/2000 but has reported to be problematic with Windows XP. Users of version 1.1 should obtain the patch located at http://www.comet.ucar.edu/help/ModuleSupport/matrix_problem.htm or use the new, Web-based module.

Estimated time to complete: 3-4 h

Description:
In this Southern Hemisphere-focused module, the student can work through one major Australian severe thunderstorm event in detail and examine aspects of two other severe thunderstorm events as well. Follow a forecast time-line to assess data and make decisions from the pre-storm phase through the warning phase.



NOTE: The Bureau of Meteorology owns this module, NOT the COMET Program.

Estimated time to complete: 4-6 h

Description:
This module deals with identifying the characteristics of radiation versus advection fog events, determining which process is dominating, and applying that understanding when making ceiling and visibility forecasts. A forecast approach using a decision tree is also discussed. This decision tree outlines the basic steps involved in applying a thorough forecast approach to fog and stratus events. The module is based on live teletraining sessions offered in 2003 as part of the Distance Learning Aviation Course 1 (DLAC1) on Fog and Stratus Forecasting.

Objectives:
1. Describe the differing processes that lead to radiation fog and advection fog

2. State the two key ingredients for the formation of fog or low stratus: increasing moisture in the boundary layer or decreasing boundary layer temperatures.

3. Properly identify which processes are dominating a particular fog or low stratus event. You can do this by:

• Examining the characteristics of the processes involved,
• Examining the low-level factors that are influencing the event, and
• Comparing these to the known characteristics, processes, and factors that distinguish a radiation event from an advective event.

Estimated time to complete: 2 h

Description:
This is the second module in the Mesoscale Meteorology Primer series. This module starts with a forecast scenario that occurs during a winter radiation fog event in the Central Valley of California. After that, a conceptual section covers the physical processes of radiation fog through its life cycle. Operational sections addressing fog detection and forecasting conclude the module

Objectives:
At the end of the module you should be able to do the following things:

With Regard to the Preconditioning Environment:

• Identify key conditions and ingredients necessary for development of radiation fog
• Discriminate between large-scale low-level environments that are favorable and unfavorable for development of radiation fog
• Describe the sequence of key surface and boundary layer processes that prepare the low-level environment for development of radiation fog
• Demonstrate an understanding of how surface cooling dries the micro-boundary layer and prevents low-level condensation from being deposited onto the surface
• Rank various surface and surface cover types in terms of the relative speed with which low-level air in contact with them will reach saturation

With Regard to Initiation and Growth:

• Identify levels at which radiative cooling is most active at various stages of the fog initiation and growth process
• Demonstrate an understanding of the effects that various condensation nuclei types and concentrations have on fog formation
• Sequence the key processes and events that occur during formation of a layer of radiation fog
• Demonstrate an understanding of how the fog-top inversion is created by the fog itself
• Demonstrate an understanding of influences that heat flux from the surface have on a fog layer during its initiation and growth

With Regard to Maintenance Phase:

• Describe key processes that balance one another to allow a fog layer to maintain a relatively constant depth
• Identify conditions in and above a fog-top layer that support continued condensate production
• Identify conditions in and above a fog-top layer that restrict further deepening
• Demonstrate an understanding of the effects that various condensation nuclei types and concentrations have on fog maintenance
• Demonstrate an understanding of the effects that introduction of an overlying cloud layer have on a mature fog layer at the surface
• Demonstrate an understanding of influences that heat flux from the surface have on a mature fog layer
• Identify the typical level of a fog-top inversion
• Demonstrate an understanding of how the fog-top inversion is maintained by various processes at and above the top of the fog layer

With Regard to Dissipation Phase:

• Identify key processes that contribute to the dissipation of a fog layer
• Apply a droplet settling rate calculation to predict the time required for a given depth of fog layer to settle to the ground in the absence of any new condensate production
• Demonstrate an understanding of how radiative heating contributes to dissipation of a fog layer
• Demonstrate an understanding of how turbulent mixing contributes to dissipation of a fog layer
• Demonstrate an understanding of how changes in low-level winds can contribute to dissipation of a fog layer
• Demonstrate an understanding of how introduction of an overlying cloud layer can contribute to dissipation of a fog layer
With Regard to Detecting Fog:
• Identify surface observations that show atmospheric conditions conducive to radiation fog
• Identify soundings that show atmospheric conditions conducive to radiation fog
• Identify fog in satellite images
• Describe the limitations of infrared satellite images for detecting radiation fog

With Regard to Forecasting Fog:

• Describe the diurnal cycle of radiation fog occurrence
• Demonstrate and understanding of the strong seasonal dependence of radiation fog occurrence in at least two localities
• Describe which forecast products best show the atmospheric conditions conducive to radiation fog
• Describe the limitations of numerical forecast models in predicting radiation fog

Estimated time to complete: 2 h

Description:
This module provides a basic understanding of why gap winds occur, their typical structures, and how gap wind strength and extent are controlled by larger-scale, or synoptic, conditions. You will learn about a number of important gap flows in coastal regions around the world, with special attention given to comprehensively documented gap wind cases in the Strait of Juan de Fuca and the Columbia River Gorge. Basic techniques for evaluating and predicting gap flows are presented. The module reviews the capabilities and limitations of the current generation of mesoscale models in producing realistic gap winds. By the end of this module, you should have sufficient background to diagnose and forecast gap flows around the world, and to use this knowledge to understand their implications for operational decisions. Other features in this module include a concise summary for quick reference and a final exam to test your knowledge. Like other modules in the Mesoscale Meteorology Primer, this module comes with audio narration, rich graphics, and a companion print version.

Objectives:
After completing this module, the learner should be able to do the following:

With regard to the description of gap winds:
• Recall where in a gap the strongest wind speeds are typically observed.
• Describe the different kinds of topographic gaps and their effect on gap flow.
• List at least 3 natural hazards that may be associated with gap winds.

With regard to the structure of gap winds:
• Describe how wind speed varies through the gap during a gap flow event.
• Describe the temperature profile through a gap during a gap flow event.
• Describe the pressure profile through a gap during a gap flow event.

With regard to the origin of gap flows:
• Describe the conditions required for geostrophic flow.
• Recall that gap winds are typically non-geostrophic.
• Describe the origin of the pressure gradients that occur across gaps.
• Recall that the thinning of low-level cool air at a gap exit can increase the pressure gradient across a gap.
• Recall that adiabatic warming of downslope winds can increase the pressure gradient across a gap.

With regard to forecasting gap winds:
• Qualitatively describe how varying the following factors affects wind speed through a gap:
   * Pressure gradient
   * Surface roughness
   * Gap length
   * Temperature
• Describe the horizontal resolution of a mesoscale model required to accurately forecast flow through a gap.

Estimated time to complete: 1.5-2 h

Description:
This module provides a brief overview of Buoyancy and CAPE. Topics covered include the origin of atmospheric buoyancy, estimating buoyancy using the CAPE and Lifted Index, factors that affect buoyancy including entrainment of mid-level air, water loading, convective inhibition, and the origin of convective downdrafts. This module delivers instruction with audio narration, rich graphics, and a companion print version.

Objectives:
Terminal Objectives
By the end of this module you will be able to do the following:
1. Describe how buoyancy contributes to formation of a convective storm and its related updrafts and downdrafts
2. Define CAPE, LI, and CIN and describe how they can be used to forecast convective activity

Enabling Objectives
By the end of this module you will be able to do the following:
1. Define buoyancy and list factors that tend to increase buoyancy
2. Describe the life cycle of a convective storm
3. Define CAPE and describe how CAPE is determined on a skew-T/log-P diagram
4. Define Lifted Index (LI) and describe how LI is determined on a skew-T/log-P diagram
5. Describe how CAPE differs from Lifted Index
6. Define Convective Inhibition (CIN) and list factors that tend to increase CIN
7. Given 2 soundings, choose the soundings that will give the stronger updraft or downdraft

Estimated time to complete: 1 h

Description:
This module discusses the role of wind shear in the structure and evolution of convective storms. Using the concept of horizontal vorticity, the module demonstrates how shear enhances uplift, leading to longer-lived supercell and multicell storms. The module also explores the role of shear in the development of mesoscale convective systems, including bow echoes and squall lines. Most of the material in this module previously appeared in the COMET modules developed with Dr. Morris Weisman. This version includes a concise summary for quick reference and a final exam to test your knowledge. The module comes with audio narration, rich graphics, and a companion print version.

Objectives:
Terminal Objectives
By the end of this module you will be able to describe the influence that vertical wind shear has on convective storm behavior

Enabling Objectives
By the end of this module you will be able to do the following:
1. Describe how and where interaction between a thunderstorm outflow (the cold pool) and the environmental wind shear lead to enhanced uplift and formation of new convective cells
2. Describe the vertical wind shear conditions that maximize the uplift along the downshear edge of the cold pool
3. Describe the origin of updraft tilt in a convective cell
4. Describe the different vertical shear characteristics for supercell storms and mesoscale convective systems (MCSs)

Estimated time to complete: 60 min

Description:
In order to assess whether a fog or stratus event is possible, you must evaluate the synoptic-scale influences that will drive the local conditions. In this module, we examine several common synoptic situations to understand the processes involved in fog or low stratus development. Most of these are forced primarily by advective or dynamic processes (although radiation does play a role). A more detailed discussion of radiation processes is contained in the Radiation Fog module. This module is part of the Distance Learning Course 1: Forecasting Fog and Low Stratus.

Objectives:
• Identify the large-scale and local conditions that support the development, maintenance, and dissipation of fog/stratus events
• Identify several synoptic regimes that can result in advection or radiation fog and the processes that contribute to fog formation, maintenance, and dissipation for each

Estimated time to complete: 2-3 h

Description:
This Webcast, is an expert lecture by Dr. Roland Madden, where he describes the important climate-moderating feature, the Madden-Julian oscillation which is known more commonly as the MJO. The Webcast is presented in five sections and covers the identification and variability of the MJO. He also introduces some of the many global weather impacts that are associated with MJO occurrences. A forecaster who attended the original classroom presentation had the following to say…“This [lecture] was really the best yet! And hearing it from the "father" of the MJO made it so much better. It was so easy for me to empirically relate my years of observing the weather to this cycle. I am convinced this is where we
can make the money in the improvement of 2 to 4 week forecasts in the next several years.”

Estimated time to complete: 42 min

Description:
This is a foundation module in the Mesoscale Meteorology Primer series. Topics covered include up- and downslope breezes, up- and down-valley winds, associated hazards, and forecasting techniques. Like other modules in the Mesoscale Meteorology Primer, this module comes with audio narration, rich graphics, and a companion print version.

Objectives:
Terminal Objectives
By the end of this module you will be able to do the following:
1. Describe how, why, when, and where mountain/valley breezes occur.
2. List the forecast concerns and aviation hazards associated with mountain/valley breezes.

Enabling Objectives
By the end of this module you will be able to do the following:
1. Describe when and where mountain/valley breezes form, including their diurnal cycle.
2. List the forecast concerns and aviation hazards associated with mountain/valley breezes.
3. Describe the processes that lead to slope winds.
4. Describe how topography may affect mountain/valley breezes.
5. Describe how satellite imagery can assist in detecting mountain/valley breezes.

Estimated time to complete: 30 min

Description:
This is part of the Physical Processes Professional Competency Unit of the Forecasting Low-Altitude Clouds and Fog for Aviation Operations Professional Development Series. West Coast Fog discusses the climatology, physical
processes, and evolution of hot spell fogs along the U.S. West Coast.

Objectives:
The goal of this training module is to help you increase your understanding of how radiation fog forms, grows, and dissipates. Such understanding, in turn, can help you more efficiently and accurately evaluate the ability of a given atmospheric environment to generate and/or maintain radiation fog.
Performance Objectives
With Regard to Climatology
Basic Level Competencies:
• Identify coastal regions worldwide where (west coast-type) fogs occur
• For each region, state the seasons of highest and lowest frequency
With Regard to the Preconditioning Environment:
Basic Level Competencies:
• Identify typical synoptic-scale patterns associated with preconditioning processes that prepare the coastal environment for fog formation
• List low-level and sea surface conditions that are typically present prior to onset of the fog formation cycle
Advanced Level Competencies:
• Sequence key processes and events that occur during the preconditioning phase
• Demonstrate an understanding of how/why the surface inversion forms as a result of hot dry offshore winds
• Describe* how/why/where coastal upwelling occurs
With Regard to Formation:
Basic Level Competencies:
• Identify typical synoptic-scale pattern transitions associated with the formation phase
• Identify the key processes and events that occur during fog formation.
Advanced Level Competencies:
• Apply rules that describe the relationships between SST, inversion base, LCL, MCL, etc.
With Regard to Growth and Maturity:
Basic Level Competencies:
Describe the continued deepening and horizontal growth of the fog
• State the typical maximum height that the inversion can reach with cloud still extending to the surface
• Describe diurnal cycles (including stratus raising/lowering)
Advanced Level Competencies:
• Demonstrate an understanding of the roles that coastal surges can play
With Regard to Fog Dissipation and/or Stratus formation:
Basic Level Competencies:
• List processes that can result in fog dissipation (advection over land, warmer water, synoptic systems, solar radiation, the start of a new cycle)
• Identify typical synoptic-scale patterns that can destroy fog regimes in MBL
• Sequence the major events that comprise the ~15-day warm season fog cycle in this region
Advanced Level Competencies:
• Describe how the fog erodes upward to form the marine stratus regime that was present prior to fog formation
• State general rule regarding relationship between sun angle and fog dissipation through insolation
• Demonstrate an understanding of how/why dissipation occurs when the MCL reaches the base of the inversion

Estimated time to complete: 1 hr

Description:
This module discusses how to apply various observational data and remote sensing tools such as satellite, METARS, soundings, profilers, radar, and model analyses to diagnose the potential for fog and/or low stratus. Various forecast tools (such as model forecast fields, forecast soundings, and BUFKIT) used to assess fog and/or low stratus potential onset, intensity, and duration are also examined. This module is part of the Distance Learning Course 1: Forecasting Fog and Low Stratus.

Objectives:
• Apply various observational data and remote sensing tools such as satellite, METARS, soundings, profilers, radar, and model analyses to diagnose the potential for fog and/or low stratus
• Apply various forecast tools such as model forecast fields, forecast soundings, and BUFKIT to assess fog and/or low stratus potential onset, intensity, and duration

Estimated time to complete: 3 h

Description:
This module deals with identifying the characteristics of radiation versus advection fog events, determining which process is dominating, and applying that understanding when making ceiling and visibility forecasts. A forecast approach using a decision tree is also discussed. This decision tree outlines the basic steps involved in applying a thorough forecast approach to fog and stratus events. The module is based on live teletraining sessions offered in 2003 as part of the Distance Learning Aviation Course 1 (DLAC1) on Fog and Stratus Forecasting.

Objectives:
1. Describe the differing processes that lead to radiation fog and advection fog

2. State the two key ingredients for the formation of fog or low stratus: increasing moisture in the boundary layer or decreasing boundary layer temperatures.

3. Properly identify which processes are dominating a particular fog or low stratus event. You can do this by:

• Examining the characteristics of the processes involved,
• Examining the low-level factors that are influencing the event, and
• Comparing these to the known characteristics, processes, and factors that distinguish a radiation event from an advective event.

Estimated time to complete: 2 h

Description:
Forecasting Dust Storms is the latest module in the Mesoscale Meteorology Primer. The module starts by discussing the conditions required for a dust storm, including an appropriate source of dust, sufficient wind and turbulence, and an unstable atmosphere. The module then explores the fate of dust in the atmosphere including dispersion, advection, and settling. The concluding section on forecasting examines a case in the Middle East and demonstrates the use of a mesoscale NWP model, as well as next-generation dust forecasting models.

Objectives:
After completing this module, the learner should be able to do the following things:

With regard to dust storm characteristics:

• Describe how visibility varies near severe dust storms
• Recall the average height of dust storms
With regard to sources of dust:
• Describe the soil types in appropriate source regions for dust storms
• Recall that blowing dust usually does not occur for at least 24 hours after a rainfall
• Identify potential source regions with satellite imagery

With regard to atmospheric conditions required for dust storms:

• Recall the threshold wind speed for lifting fine dust particles.
• Describe the atmospheric conditions that promote lofting of dust in terms of stability and turbulence
• List the 3 ways that turbulence typically arises in the atmosphere
• Describe the effect of nightfall on dust storms

With regard to the dissipation and dispersion of dust storms:

• Describe the atmospheric factors that influence the dispersion of dust
• Describe the effect of precipitation on suspended dust and why this occurs
• Recall how quickly dust settles once winds die down

With regard to the climatology of dust storms:

• List the most common synoptic patterns for raising dust in the Middle East
• Define Shamal
• List at least 3 mesoscale weather phenomena that result in dust storms
• Describe how haboobs and dust devils originate
• Describe how winter dust storms differ from summer dust storms

With regard to the satellite detection of blowing dust:

• Describe how dust appears on IR images, during both day and night and over both land and water
• Describe how dust appears on visible images, during both day and night and over both land and water
• Describe the advantages of imagery from polar orbiting and geostationary satellites
• With regard to forecasting dust storms:
• List the tools available for observing dust storms.
• Describe how mesoscale NWP models can help with a dust storm prediciton
• List the dust storm forecasting models and describe their respective advantages

Estimated time to complete: 2 h

Description:
This is the second module in the Mesoscale Meteorology Primer series. This module starts with a forecast scenario that occurs during a winter radiation fog event in the Central Valley of California. After that, a conceptual section covers the physical processes of radiation fog through its life cycle. Operational sections addressing fog detection and forecasting conclude the module

Objectives:
At the end of the module you should be able to do the following things:

With Regard to the Preconditioning Environment:

• Identify key conditions and ingredients necessary for development of radiation fog
• Discriminate between large-scale low-level environments that are favorable and unfavorable for development of radiation fog
• Describe the sequence of key surface and boundary layer processes that prepare the low-level environment for development of radiation fog
• Demonstrate an understanding of how surface cooling dries the micro-boundary layer and prevents low-level condensation from being deposited onto the surface
• Rank various surface and surface cover types in terms of the relative speed with which low-level air in contact with them will reach saturation

With Regard to Initiation and Growth:

• Identify levels at which radiative cooling is most active at various stages of the fog initiation and growth process
• Demonstrate an understanding of the effects that various condensation nuclei types and concentrations have on fog formation
• Sequence the key processes and events that occur during formation of a layer of radiation fog
• Demonstrate an understanding of how the fog-top inversion is created by the fog itself
• Demonstrate an understanding of influences that heat flux from the surface have on a fog layer during its initiation and growth

With Regard to Maintenance Phase:

• Describe key processes that balance one another to allow a fog layer to maintain a relatively constant depth
• Identify conditions in and above a fog-top layer that support continued condensate production
• Identify conditions in and above a fog-top layer that restrict further deepening
• Demonstrate an understanding of the effects that various condensation nuclei types and concentrations have on fog maintenance
• Demonstrate an understanding of the effects that introduction of an overlying cloud layer have on a mature fog layer at the surface
• Demonstrate an understanding of influences that heat flux from the surface have on a mature fog layer
• Identify the typical level of a fog-top inversion
• Demonstrate an understanding of how the fog-top inversion is maintained by various processes at and above the top of the fog layer

With Regard to Dissipation Phase:

• Identify key processes that contribute to the dissipation of a fog layer
• Apply a droplet settling rate calculation to predict the time required for a given depth of fog layer to settle to the ground in the absence of any new condensate production
• Demonstrate an understanding of how radiative heating contributes to dissipation of a fog layer
• Demonstrate an understanding of how turbulent mixing contributes to dissipation of a fog layer
• Demonstrate an understanding of how changes in low-level winds can contribute to dissipation of a fog layer
• Demonstrate an understanding of how introduction of an overlying cloud layer can contribute to dissipation of a fog layer
With Regard to Detecting Fog:
• Identify surface observations that show atmospheric conditions conducive to radiation fog
• Identify soundings that show atmospheric conditions conducive to radiation fog
• Identify fog in satellite images
• Describe the limitations of infrared satellite images for detecting radiation fog

With Regard to Forecasting Fog:

• Describe the diurnal cycle of radiation fog occurrence
• Demonstrate and understanding of the strong seasonal dependence of radiation fog occurrence in at least two localities
• Describe which forecast products best show the atmospheric conditions conducive to radiation fog
• Describe the limitations of numerical forecast models in predicting radiation fog

Estimated time to complete: 2 h

Description:
This module provides a brief overview of Buoyancy and CAPE. Topics covered include the origin of atmospheric buoyancy, estimating buoyancy using the CAPE and Lifted Index, factors that affect buoyancy including entrainment of mid-level air, water loading, convective inhibition, and the origin of convective downdrafts. This module delivers instruction with audio narration, rich graphics, and a companion print version.

Objectives:
Terminal Objectives
By the end of this module you will be able to do the following:
1. Describe how buoyancy contributes to formation of a convective storm and its related updrafts and downdrafts
2. Define CAPE, LI, and CIN and describe how they can be used to forecast convective activity

Enabling Objectives
By the end of this module you will be able to do the following:
1. Define buoyancy and list factors that tend to increase buoyancy
2. Describe the life cycle of a convective storm
3. Define CAPE and describe how CAPE is determined on a skew-T/log-P diagram
4. Define Lifted Index (LI) and describe how LI is determined on a skew-T/log-P diagram
5. Describe how CAPE differs from Lifted Index
6. Define Convective Inhibition (CIN) and list factors that tend to increase CIN
7. Given 2 soundings, choose the soundings that will give the stronger updraft or downdraft

Estimated time to complete: 1 h

Description:
This module discusses the role of wind shear in the structure and evolution of convective storms. Using the concept of horizontal vorticity, the module demonstrates how shear enhances uplift, leading to longer-lived supercell and multicell storms. The module also explores the role of shear in the development of mesoscale convective systems, including bow echoes and squall lines. Most of the material in this module previously appeared in the COMET modules developed with Dr. Morris Weisman. This version includes a concise summary for quick reference and a final exam to test your knowledge. The module comes with audio narration, rich graphics, and a companion print version.

Objectives:
Terminal Objectives
By the end of this module you will be able to describe the influence that vertical wind shear has on convective storm behavior

Enabling Objectives
By the end of this module you will be able to do the following:
1. Describe how and where interaction between a thunderstorm outflow (the cold pool) and the environmental wind shear lead to enhanced uplift and formation of new convective cells
2. Describe the vertical wind shear conditions that maximize the uplift along the downshear edge of the cold pool
3. Describe the origin of updraft tilt in a convective cell
4. Describe the different vertical shear characteristics for supercell storms and mesoscale convective systems (MCSs)

Estimated time to complete: 60 min

Description:
Meteorologists typically examine atmospheric soundings in the course of preparing a weather forecast. The skew-T / log-P diagram provides the preferred method for analyzing these soundings. This module comprehensively examines the use of the skew-T diagram. It explores thermodynamic properties, convective parameters, stability assessment, and several forecast applications. The module is designed for both instruction and reference. It also comes with an interactive Web-based skew-T diagram that calculates several common forecast parameters.

Objectives:
Module Goal
The goal of this module is to teach the novice forecaster to effectively use the skew-T/log-P diagram. After completing the module, they should be able to read and interpret a sounding plotted on a skew-T/log P diagram and apply that information to a weather forecast.

Performance Objectives

1. Given a skew-T/log-P diagram, identify and describe the various lines.


2. Given a sounding plotted on a skew-T/log-P diagram:




• Read or calculate the thermodynamic properties at various levels.


• Determine the convective levels, including the LCL, CCL, LFC, MCL, EL, and MPL.


• Determine stability indices such as LI, SSI, KI, TT, and SWEAT and use them to assess the potential for severe weather.




3. Describe how CAPE and CIN are determined.


4. List and describe the different types of stability and identify them in a sounding plotted on a skew-T diagram


5. List and describe the different types of lapse rates and relate them to stability.


6. List and describe processes that alter stability and give examples of common cases where those processes occur.


7. Given a suitable synoptic environment and a sounding plotted on a skew-T/log-P diagram, interpret the sounding with regard to common forecast problems.

Estimated time to complete: 6-8 h

Description:
This is part of the Physical Processes Professional Competency Unit of the Forecasting Low-Altitude Clouds and Fog for Aviation Operations Professional Development Series. West Coast Fog discusses the climatology, physical
processes, and evolution of hot spell fogs along the U.S. West Coast.

Objectives:
The goal of this training module is to help you increase your understanding of how radiation fog forms, grows, and dissipates. Such understanding, in turn, can help you more efficiently and accurately evaluate the ability of a given atmospheric environment to generate and/or maintain radiation fog.
Performance Objectives
With Regard to Climatology
Basic Level Competencies:
• Identify coastal regions worldwide where (west coast-type) fogs occur
• For each region, state the seasons of highest and lowest frequency
With Regard to the Preconditioning Environment:
Basic Level Competencies:
• Identify typical synoptic-scale patterns associated with preconditioning processes that prepare the coastal environment for fog formation
• List low-level and sea surface conditions that are typically present prior to onset of the fog formation cycle
Advanced Level Competencies:
• Sequence key processes and events that occur during the preconditioning phase
• Demonstrate an understanding of how/why the surface inversion forms as a result of hot dry offshore winds
• Describe* how/why/where coastal upwelling occurs
With Regard to Formation:
Basic Level Competencies:
• Identify typical synoptic-scale pattern transitions associated with the formation phase
• Identify the key processes and events that occur during fog formation.
Advanced Level Competencies:
• Apply rules that describe the relationships between SST, inversion base, LCL, MCL, etc.
With Regard to Growth and Maturity:
Basic Level Competencies:
Describe the continued deepening and horizontal growth of the fog
• State the typical maximum height that the inversion can reach with cloud still extending to the surface
• Describe diurnal cycles (including stratus raising/lowering)
Advanced Level Competencies:
• Demonstrate an understanding of the roles that coastal surges can play
With Regard to Fog Dissipation and/or Stratus formation:
Basic Level Competencies:
• List processes that can result in fog dissipation (advection over land, warmer water, synoptic systems, solar radiation, the start of a new cycle)
• Identify typical synoptic-scale patterns that can destroy fog regimes in MBL
• Sequence the major events that comprise the ~15-day warm season fog cycle in this region
Advanced Level Competencies:
• Describe how the fog erodes upward to form the marine stratus regime that was present prior to fog formation
• State general rule regarding relationship between sun angle and fog dissipation through insolation
• Demonstrate an understanding of how/why dissipation occurs when the MCL reaches the base of the inversion

Estimated time to complete: 1 hr

Description:
"Writing TAFs for Convective Weather" uses a case to show how special tools and techniques can be used to produce a Practically Perfect TAF (PPTAF) for convection. The unit examines how to create TAFs for different types of convection and how to effectively communicate logic and uncertainty in an aviation forecast discussion (AvnFD) or by other means. It also addresses maintaining an effective TAF weather watch and updating the TAF proactively.

Objectives:
1. Describe how general convective hazards might impact airport operations.
2. Describe how the unique characteristics of each convective type relate to creating a TAF.
3. List the strengths and weaknesses of using BUFKIT, aircraft weather data, AWIPS Time-of-Arrival (TOA)/Lead Time and Time Series tools, satellite data, climatology, and other special tools for creating a TAF for convection.
4. Explain why the PPTAF procedure needs to be revised for convection and why the use of special tools is so important for this process.
5. Produce a PPTAF for a mesoscale convective system, air mass thunderstorms, supercell thunderstorms, or microbursts
6. Effectively articulate forecast logic and uncertainty about a TAF in an Aviation Forecast Discussion (AvnFD).
7. Ensure a TAF is consistent with previous TAFs or other products issued by both local offices and national centers.
8. Be able to run an effective weather watch by identifying beforehand when a TAF update is warranted.
9. Show the ability to update proactively, rather than in a reactive fashion.
10. Identify when coordination is necessary for the TAF and with whom it should be conducted.

Estimated time to complete: 2 h

Description:
"Writing TAFs for Winds and LLWS" is the third unit in the Distance Learning Aviation Course 2 (DLAC2) series on producing TAFs that meet the needs of the aviation community. In addition to providing information about tools for diagnosing wind and wind impacts, the module extends the Practically Perfect TAF (PPTAF) process to address airport-specific criteria. By understanding the criteria at airports for which they produce TAFs, forecasters will be better able to produce a Practically Perfect Site-Specific TAF (PPSST). The unit also examines how to effectively communicate logic and uncertainty in an aviation forecast discussion (AvnFD) and addresses maintaining an effective TAF weather watch and updating the TAF proactively.

Objectives:
* Describe the importance of accurate wind forecasts to various customers
Issue Practically Perfect TAFs that are sensitive to airport-specific criteria (i.e., PPSST—Practically Perfect Site Specific TAFs)
* Create a PPSST that meets customer needs for different airports
* Use tools, products, and data to limit uncertainty in wind and LLWS forecasts
* Use  “VRB” (Variable), “G” (Gust), and “LLWS” appropriately in a TAF
* Issue TAFs proactively and identify situations when it is best to “sit on” a TAF
* Make appropriate use of the AvnFD to express uncertainty about these phenomena
* Ensure terminal forecasts are consistent with warning, forecast, and guidance products from national aviation centers
* Demonstrate the ability to collaborate effectively when preparing a terminal forecast

Estimated time to complete: 3 h

Description:
This module discusses how to apply various observational data and remote sensing tools such as satellite, METARS, soundings, profilers, radar, and model analyses to diagnose the potential for fog and/or low stratus. Various forecast tools (such as model forecast fields, forecast soundings, and BUFKIT) used to assess fog and/or low stratus potential onset, intensity, and duration are also examined. This module is part of the Distance Learning Course 1: Forecasting Fog and Low Stratus.

Objectives:
• Apply various observational data and remote sensing tools such as satellite, METARS, soundings, profilers, radar, and model analyses to diagnose the potential for fog and/or low stratus
• Apply various forecast tools such as model forecast fields, forecast soundings, and BUFKIT to assess fog and/or low stratus potential onset, intensity, and duration

Estimated time to complete: 3 h

Description:
In this Southern Hemisphere-focused module, the student can work through one major Australian severe thunderstorm event in detail and examine aspects of two other severe thunderstorm events as well. Follow a forecast time-line to assess data and make decisions from the pre-storm phase through the warning phase.



NOTE: The Bureau of Meteorology owns this module, NOT the COMET Program.

Estimated time to complete: 4-6 h

Description:
Fog frequently forms in response to dynamically forced changes in the boundary layer. This module examines dynamically forced fog in the coastal and marine environment, focusing on advection fog, steam fog, and west coast type fog. The focus of the module is on the boundary layer evolution of air parcels as they traverse trajectories over land and water. The module also examines mesoscale effects that impact the distribution of fog and low-level stratus over short distances. A general discussion of forecast products and methodologies concludes the module.

Objectives:
After completing this module, the learner should be able to do the following things:

With regard to the general features of dynamically forced fog and stratus:

• Describe the differences in boundary layer characteristics and evolution for advection, West Coast, and steam fog in a marine environment
• Describe the differences in synoptic environments for advection, West Coast, and steam fog in a marine environment
• Describe the relationship of sea surface temperature to fog formation for advection, West Coast, and steam fog in a marine environment
With regard to advection fog:
• Describe the general synoptic environment that is conducive to fog formation
• List at least 2 ways that subtropical high-pressure systems contribute to the formation of advection fog
• Describe the evolution of the boundary layer along an air parcel trajectory that leads to advection fog
• Describe how sea surface temperature changes along an air parcel trajectory that leads to advection fog
• Recall the origins of strong sea surface temperature gradients
• On a world map, identify areas prone to advection fog
• Recall the seasonality of advection fog

With regard to West Coast fog and low stratus:

• Describe the general synoptic environment that is conducive to fog formation
• List at least 2 ways that subtropical high-pressure systems contribute to the formation of West Coast fog and low stratus
• Describe the evolution of the boundary layer along an air parcel trajectory that leads to West Coast fog and low stratus
• List at least 2 ways that the boundary layer cools to saturation in a West Coast fog/stratus event.
• Recall the role of upwelling in the formation of West Coast fog and low stratus
• On a world map, identify areas prone to West Coast fog and low stratus
• Recall the seasonality of West Coast fog and low stratus
With regard to steam fog:
• Describe the general synoptic environment that is conducive to fog formation
• Describe the characteristics and evolution of the boundary layer along an air parcel trajectory that leads to steam fog
• On a world map, identify areas prone to steam fog
• Recall the seasonality of steam fog events

With regard to mesoscale influences upon dynamically forced fog:

• Describe the effects of coastal topography in fog formation
• Describe how coastal jets affect fog formation and dissipation
• Describe how sea breezes affect fog formation and dissipation
• Describe the impact of local variations in sea surface temperature on fog formation and dissipation

With regard to forecasting dynamically forced fog:

• Describe the general approach to forecasting fog
• List at least 4 critical atmospheric fields to monitor in plan view when forecasting fog
• List at least 4 critical atmospheric fields to monitor in vertical profiles when forecasting fog
• Describe the limitations of NWP models in fog forecasting

Estimated time to complete: 3 h

Description:
This module deals with identifying the characteristics of radiation versus advection fog events, determining which process is dominating, and applying that understanding when making ceiling and visibility forecasts. A forecast approach using a decision tree is also discussed. This decision tree outlines the basic steps involved in applying a thorough forecast approach to fog and stratus events. The module is based on live teletraining sessions offered in 2003 as part of the Distance Learning Aviation Course 1 (DLAC1) on Fog and Stratus Forecasting.

Objectives:
1. Describe the differing processes that lead to radiation fog and advection fog

2. State the two key ingredients for the formation of fog or low stratus: increasing moisture in the boundary layer or decreasing boundary layer temperatures.

3. Properly identify which processes are dominating a particular fog or low stratus event. You can do this by:

• Examining the characteristics of the processes involved,
• Examining the low-level factors that are influencing the event, and
• Comparing these to the known characteristics, processes, and factors that distinguish a radiation event from an advective event.

Estimated time to complete: 2 h

Description:
This is the second module in the Mesoscale Meteorology Primer series. This module starts with a forecast scenario that occurs during a winter radiation fog event in the Central Valley of California. After that, a conceptual section covers the physical processes of radiation fog through its life cycle. Operational sections addressing fog detection and forecasting conclude the module

Objectives:
At the end of the module you should be able to do the following things:

With Regard to the Preconditioning Environment:

• Identify key conditions and ingredients necessary for development of radiation fog
• Discriminate between large-scale low-level environments that are favorable and unfavorable for development of radiation fog
• Describe the sequence of key surface and boundary layer processes that prepare the low-level environment for development of radiation fog
• Demonstrate an understanding of how surface cooling dries the micro-boundary layer and prevents low-level condensation from being deposited onto the surface
• Rank various surface and surface cover types in terms of the relative speed with which low-level air in contact with them will reach saturation

With Regard to Initiation and Growth:

• Identify levels at which radiative cooling is most active at various stages of the fog initiation and growth process
• Demonstrate an understanding of the effects that various condensation nuclei types and concentrations have on fog formation
• Sequence the key processes and events that occur during formation of a layer of radiation fog
• Demonstrate an understanding of how the fog-top inversion is created by the fog itself
• Demonstrate an understanding of influences that heat flux from the surface have on a fog layer during its initiation and growth

With Regard to Maintenance Phase:

• Describe key processes that balance one another to allow a fog layer to maintain a relatively constant depth
• Identify conditions in and above a fog-top layer that support continued condensate production
• Identify conditions in and above a fog-top layer that restrict further deepening
• Demonstrate an understanding of the effects that various condensation nuclei types and concentrations have on fog maintenance
• Demonstrate an understanding of the effects that introduction of an overlying cloud layer have on a mature fog layer at the surface
• Demonstrate an understanding of influences that heat flux from the surface have on a mature fog layer
• Identify the typical level of a fog-top inversion
• Demonstrate an understanding of how the fog-top inversion is maintained by various processes at and above the top of the fog layer

With Regard to Dissipation Phase:

• Identify key processes that contribute to the dissipation of a fog layer
• Apply a droplet settling rate calculation to predict the time required for a given depth of fog layer to settle to the ground in the absence of any new condensate production
• Demonstrate an understanding of how radiative heating contributes to dissipation of a fog layer
• Demonstrate an understanding of how turbulent mixing contributes to dissipation of a fog layer
• Demonstrate an understanding of how changes in low-level winds can contribute to dissipation of a fog layer
• Demonstrate an understanding of how introduction of an overlying cloud layer can contribute to dissipation of a fog layer
With Regard to Detecting Fog:
• Identify surface observations that show atmospheric conditions conducive to radiation fog
• Identify soundings that show atmospheric conditions conducive to radiation fog
• Identify fog in satellite images
• Describe the limitations of infrared satellite images for detecting radiation fog

With Regard to Forecasting Fog:

• Describe the diurnal cycle of radiation fog occurrence
• Demonstrate and understanding of the strong seasonal dependence of radiation fog occurrence in at least two localities
• Describe which forecast products best show the atmospheric conditions conducive to radiation fog
• Describe the limitations of numerical forecast models in predicting radiation fog

Estimated time to complete: 2 h

Description:
This module provides a basic understanding of why gap winds occur, their typical structures, and how gap wind strength and extent are controlled by larger-scale, or synoptic, conditions. You will learn about a number of important gap flows in coastal regions around the world, with special attention given to comprehensively documented gap wind cases in the Strait of Juan de Fuca and the Columbia River Gorge. Basic techniques for evaluating and predicting gap flows are presented. The module reviews the capabilities and limitations of the current generation of mesoscale models in producing realistic gap winds. By the end of this module, you should have sufficient background to diagnose and forecast gap flows around the world, and to use this knowledge to understand their implications for operational decisions. Other features in this module include a concise summary for quick reference and a final exam to test your knowledge. Like other modules in the Mesoscale Meteorology Primer, this module comes with audio narration, rich graphics, and a companion print version.

Objectives:
After completing this module, the learner should be able to do the following:

With regard to the description of gap winds:
• Recall where in a gap the strongest wind speeds are typically observed.
• Describe the different kinds of topographic gaps and their effect on gap flow.
• List at least 3 natural hazards that may be associated with gap winds.

With regard to the structure of gap winds:
• Describe how wind speed varies through the gap during a gap flow event.
• Describe the temperature profile through a gap during a gap flow event.
• Describe the pressure profile through a gap during a gap flow event.

With regard to the origin of gap flows:
• Describe the conditions required for geostrophic flow.
• Recall that gap winds are typically non-geostrophic.
• Describe the origin of the pressure gradients that occur across gaps.
• Recall that the thinning of low-level cool air at a gap exit can increase the pressure gradient across a gap.
• Recall that adiabatic warming of downslope winds can increase the pressure gradient across a gap.

With regard to forecasting gap winds:
• Qualitatively describe how varying the following factors affects wind speed through a gap:
   * Pressure gradient
   * Surface roughness
   * Gap length
   * Temperature
• Describe the horizontal resolution of a mesoscale model required to accurately forecast flow through a gap.

Estimated time to complete: 1.5-2 h

Description:
Meteorologists typically examine atmospheric soundings in the course of preparing a weather forecast. The skew-T / log-P diagram provides the preferred method for analyzing these soundings. This module comprehensively examines the use of the skew-T diagram. It explores thermodynamic properties, convective parameters, stability assessment, and several forecast applications. The module is designed for both instruction and reference. It also comes with an interactive Web-based skew-T diagram that calculates several common forecast parameters.

Objectives:
Module Goal
The goal of this module is to teach the novice forecaster to effectively use the skew-T/log-P diagram. After completing the module, they should be able to read and interpret a sounding plotted on a skew-T/log P diagram and apply that information to a weather forecast.

Performance Objectives

1. Given a skew-T/log-P diagram, identify and describe the various lines.


2. Given a sounding plotted on a skew-T/log-P diagram:




• Read or calculate the thermodynamic properties at various levels.


• Determine the convective levels, including the LCL, CCL, LFC, MCL, EL, and MPL.


• Determine stability indices such as LI, SSI, KI, TT, and SWEAT and use them to assess the potential for severe weather.




3. Describe how CAPE and CIN are determined.


4. List and describe the different types of stability and identify them in a sounding plotted on a skew-T diagram


5. List and describe the different types of lapse rates and relate them to stability.


6. List and describe processes that alter stability and give examples of common cases where those processes occur.


7. Given a suitable synoptic environment and a sounding plotted on a skew-T/log-P diagram, interpret the sounding with regard to common forecast problems.

Estimated time to complete: 6-8 h

Description:
This module describes the phenomena of the sea breeze. It examines factors that lead to the formation of a sea breeze, modifying effects on sea breeze development, how mesoscale NWP models handle sea breezes, and sea breeze forecast parameters. The module places instruction in the context of a sea breeze case from Florida and compares surface and satellite observations to a model simulation using the AFWA MM5. Like other modules in the Mesoscale Meteorology Primer, this module comes with audio narration, rich graphics, and a companion print version.

Objectives:
Terminal Objectives
By the end of this module you will be able to describe how and why, when and where sea breezes occur

Enabling Objectives
By the end of this module you will be able to do the following:
1. Describe when and where sea breezes form
2. Characterize the sea breeze in terms of strength and horizontal and vertical extent
3. List the principle factors that affect sea breeze formation
4. List the sensible weather associated with formation and passage of a sea breeze front
5. Describe the use and limitations of NWP model simulations of sea breezes.
6. Describe how satellite imagery can assist in detecting sea breezes

Estimated time to complete: 1 h

Description:
"Writing TAFs for Convective Weather" uses a case to show how special tools and techniques can be used to produce a Practically Perfect TAF (PPTAF) for convection. The unit examines how to create TAFs for different types of convection and how to effectively communicate logic and uncertainty in an aviation forecast discussion (AvnFD) or by other means. It also addresses maintaining an effective TAF weather watch and updating the TAF proactively.

Objectives:
1. Describe how general convective hazards might impact airport operations.
2. Describe how the unique characteristics of each convective type relate to creating a TAF.
3. List the strengths and weaknesses of using BUFKIT, aircraft weather data, AWIPS Time-of-Arrival (TOA)/Lead Time and Time Series tools, satellite data, climatology, and other special tools for creating a TAF for convection.
4. Explain why the PPTAF procedure needs to be revised for convection and why the use of special tools is so important for this process.
5. Produce a PPTAF for a mesoscale convective system, air mass thunderstorms, supercell thunderstorms, or microbursts
6. Effectively articulate forecast logic and uncertainty about a TAF in an Aviation Forecast Discussion (AvnFD).
7. Ensure a TAF is consistent with previous TAFs or other products issued by both local offices and national centers.
8. Be able to run an effective weather watch by identifying beforehand when a TAF update is warranted.
9. Show the ability to update proactively, rather than in a reactive fashion.
10. Identify when coordination is necessary for the TAF and with whom it should be conducted.

Estimated time to complete: 2 h

Description:
"Writing TAFs for Winds and LLWS" is the third unit in the Distance Learning Aviation Course 2 (DLAC2) series on producing TAFs that meet the needs of the aviation community. In addition to providing information about tools for diagnosing wind and wind impacts, the module extends the Practically Perfect TAF (PPTAF) process to address airport-specific criteria. By understanding the criteria at airports for which they produce TAFs, forecasters will be better able to produce a Practically Perfect Site-Specific TAF (PPSST). The unit also examines how to effectively communicate logic and uncertainty in an aviation forecast discussion (AvnFD) and addresses maintaining an effective TAF weather watch and updating the TAF proactively.

Objectives:
* Describe the importance of accurate wind forecasts to various customers
Issue Practically Perfect TAFs that are sensitive to airport-specific criteria (i.e., PPSST—Practically Perfect Site Specific TAFs)
* Create a PPSST that meets customer needs for different airports
* Use tools, products, and data to limit uncertainty in wind and LLWS forecasts
* Use  “VRB” (Variable), “G” (Gust), and “LLWS” appropriately in a TAF
* Issue TAFs proactively and identify situations when it is best to “sit on” a TAF
* Make appropriate use of the AvnFD to express uncertainty about these phenomena
* Ensure terminal forecasts are consistent with warning, forecast, and guidance products from national aviation centers
* Demonstrate the ability to collaborate effectively when preparing a terminal forecast

Estimated time to complete: 3 h

Description:
This module discusses how to apply various observational data and remote sensing tools such as satellite, METARS, soundings, profilers, radar, and model analyses to diagnose the potential for fog and/or low stratus. Various forecast tools (such as model forecast fields, forecast soundings, and BUFKIT) used to assess fog and/or low stratus potential onset, intensity, and duration are also examined. This module is part of the Distance Learning Course 1: Forecasting Fog and Low Stratus.

Objectives:
• Apply various observational data and remote sensing tools such as satellite, METARS, soundings, profilers, radar, and model analyses to diagnose the potential for fog and/or low stratus
• Apply various forecast tools such as model forecast fields, forecast soundings, and BUFKIT to assess fog and/or low stratus potential onset, intensity, and duration

Estimated time to complete: 3 h

Description:
This module addresses issues surrounding the direct and indirect impacts of restricted ceilings and visibilities on aviation operations and also briefly examines their impacts on ground and marine transportation. The goal is improve forecaster awareness of how their forecasts of these events affect commercial and general aviation operation. This module is part of the Distance Learning Course 1: Forecasting Fog and Low Stratus.

Objectives:
• Increase awareness of the various users of ceilings and visibility forecasts and how forecasts of these conditions impact (both positively and negatively) aviation operations within each user group
    o Improve forecaster understanding of the impacts of reduced visibility and ceilings on commercial and general aviation operations
    o Improve forecaster understanding of the impact to aviation operations from forecasts (TAFs) of reduced ceiling and visibility due to fog and low stratus
    o Provide recommendations on how and when to amend TAFs to best reflect current and forecast conditions
• Increase awareness of the need to be knowledgeable about supported airport configurations
• Increase knowledge of critical thresholds and their variations from one airport to another and one user group to another

Estimated time to complete: 1 h

Description:
This is the second module in the Mesoscale Meteorology Primer series. This module starts with a forecast scenario that occurs during a winter radiation fog event in the Central Valley of California. After that, a conceptual section covers the physical processes of radiation fog through its life cycle. Operational sections addressing fog detection and forecasting conclude the module

Objectives:
At the end of the module you should be able to do the following things:

With Regard to the Preconditioning Environment:

• Identify key conditions and ingredients necessary for development of radiation fog
• Discriminate between large-scale low-level environments that are favorable and unfavorable for development of radiation fog
• Describe the sequence of key surface and boundary layer processes that prepare the low-level environment for development of radiation fog
• Demonstrate an understanding of how surface cooling dries the micro-boundary layer and prevents low-level condensation from being deposited onto the surface
• Rank various surface and surface cover types in terms of the relative speed with which low-level air in contact with them will reach saturation

With Regard to Initiation and Growth:

• Identify levels at which radiative cooling is most active at various stages of the fog initiation and growth process
• Demonstrate an understanding of the effects that various condensation nuclei types and concentrations have on fog formation
• Sequence the key processes and events that occur during formation of a layer of radiation fog
• Demonstrate an understanding of how the fog-top inversion is created by the fog itself
• Demonstrate an understanding of influences that heat flux from the surface have on a fog layer during its initiation and growth

With Regard to Maintenance Phase:

• Describe key processes that balance one another to allow a fog layer to maintain a relatively constant depth
• Identify conditions in and above a fog-top layer that support continued condensate production
• Identify conditions in and above a fog-top layer that restrict further deepening
• Demonstrate an understanding of the effects that various condensation nuclei types and concentrations have on fog maintenance
• Demonstrate an understanding of the effects that introduction of an overlying cloud layer have on a mature fog layer at the surface
• Demonstrate an understanding of influences that heat flux from the surface have on a mature fog layer
• Identify the typical level of a fog-top inversion
• Demonstrate an understanding of how the fog-top inversion is maintained by various processes at and above the top of the fog layer

With Regard to Dissipation Phase:

• Identify key processes that contribute to the dissipation of a fog layer
• Apply a droplet settling rate calculation to predict the time required for a given depth of fog layer to settle to the ground in the absence of any new condensate production
• Demonstrate an understanding of how radiative heating contributes to dissipation of a fog layer
• Demonstrate an understanding of how turbulent mixing contributes to dissipation of a fog layer
• Demonstrate an understanding of how changes in low-level winds can contribute to dissipation of a fog layer
• Demonstrate an understanding of how introduction of an overlying cloud layer can contribute to dissipation of a fog layer
With Regard to Detecting Fog:
• Identify surface observations that show atmospheric conditions conducive to radiation fog
• Identify soundings that show atmospheric conditions conducive to radiation fog
• Identify fog in satellite images
• Describe the limitations of infrared satellite images for detecting radiation fog

With Regard to Forecasting Fog:

• Describe the diurnal cycle of radiation fog occurrence
• Demonstrate and understanding of the strong seasonal dependence of radiation fog occurrence in at least two localities
• Describe which forecast products best show the atmospheric conditions conducive to radiation fog
• Describe the limitations of numerical forecast models in predicting radiation fog

Estimated time to complete: 2 h

Description:
This module describes the phenomena of the sea breeze. It examines factors that lead to the formation of a sea breeze, modifying effects on sea breeze development, how mesoscale NWP models handle sea breezes, and sea breeze forecast parameters. The module places instruction in the context of a sea breeze case from Florida and compares surface and satellite observations to a model simulation using the AFWA MM5. Like other modules in the Mesoscale Meteorology Primer, this module comes with audio narration, rich graphics, and a companion print version.

Objectives:
Terminal Objectives
By the end of this module you will be able to describe how and why, when and where sea breezes occur

Enabling Objectives
By the end of this module you will be able to do the following:
1. Describe when and where sea breezes form
2. Characterize the sea breeze in terms of strength and horizontal and vertical extent
3. List the principle factors that affect sea breeze formation
4. List the sensible weather associated with formation and passage of a sea breeze front
5. Describe the use and limitations of NWP model simulations of sea breezes.
6. Describe how satellite imagery can assist in detecting sea breezes

Estimated time to complete: 1 h

Description:
"Writing TAFs for Convective Weather" uses a case to show how special tools and techniques can be used to produce a Practically Perfect TAF (PPTAF) for convection. The unit examines how to create TAFs for different types of convection and how to effectively communicate logic and uncertainty in an aviation forecast discussion (AvnFD) or by other means. It also addresses maintaining an effective TAF weather watch and updating the TAF proactively.

Objectives:
1. Describe how general convective hazards might impact airport operations.
2. Describe how the unique characteristics of each convective type relate to creating a TAF.
3. List the strengths and weaknesses of using BUFKIT, aircraft weather data, AWIPS Time-of-Arrival (TOA)/Lead Time and Time Series tools, satellite data, climatology, and other special tools for creating a TAF for convection.
4. Explain why the PPTAF procedure needs to be revised for convection and why the use of special tools is so important for this process.
5. Produce a PPTAF for a mesoscale convective system, air mass thunderstorms, supercell thunderstorms, or microbursts
6. Effectively articulate forecast logic and uncertainty about a TAF in an Aviation Forecast Discussion (AvnFD).
7. Ensure a TAF is consistent with previous TAFs or other products issued by both local offices and national centers.
8. Be able to run an effective weather watch by identifying beforehand when a TAF update is warranted.
9. Show the ability to update proactively, rather than in a reactive fashion.
10. Identify when coordination is necessary for the TAF and with whom it should be conducted.

Estimated time to complete: 2 h

Description:
"Writing TAFs for Winds and LLWS" is the third unit in the Distance Learning Aviation Course 2 (DLAC2) series on producing TAFs that meet the needs of the aviation community. In addition to providing information about tools for diagnosing wind and wind impacts, the module extends the Practically Perfect TAF (PPTAF) process to address airport-specific criteria. By understanding the criteria at airports for which they produce TAFs, forecasters will be better able to produce a Practically Perfect Site-Specific TAF (PPSST). The unit also examines how to effectively communicate logic and uncertainty in an aviation forecast discussion (AvnFD) and addresses maintaining an effective TAF weather watch and updating the TAF proactively.

Objectives:
* Describe the importance of accurate wind forecasts to various customers
Issue Practically Perfect TAFs that are sensitive to airport-specific criteria (i.e., PPSST—Practically Perfect Site Specific TAFs)
* Create a PPSST that meets customer needs for different airports
* Use tools, products, and data to limit uncertainty in wind and LLWS forecasts
* Use  “VRB” (Variable), “G” (Gust), and “LLWS” appropriately in a TAF
* Issue TAFs proactively and identify situations when it is best to “sit on” a TAF
* Make appropriate use of the AvnFD to express uncertainty about these phenomena
* Ensure terminal forecasts are consistent with warning, forecast, and guidance products from national aviation centers
* Demonstrate the ability to collaborate effectively when preparing a terminal forecast

Estimated time to complete: 3 h

Description:
Fog frequently forms in response to dynamically forced changes in the boundary layer. This module examines dynamically forced fog in the coastal and marine environment, focusing on advection fog, steam fog, and west coast type fog. The focus of the module is on the boundary layer evolution of air parcels as they traverse trajectories over land and water. The module also examines mesoscale effects that impact the distribution of fog and low-level stratus over short distances. A general discussion of forecast products and methodologies concludes the module.

Objectives:
After completing this module, the learner should be able to do the following things:

With regard to the general features of dynamically forced fog and stratus:

• Describe the differences in boundary layer characteristics and evolution for advection, West Coast, and steam fog in a marine environment
• Describe the differences in synoptic environments for advection, West Coast, and steam fog in a marine environment
• Describe the relationship of sea surface temperature to fog formation for advection, West Coast, and steam fog in a marine environment
With regard to advection fog:
• Describe the general synoptic environment that is conducive to fog formation
• List at least 2 ways that subtropical high-pressure systems contribute to the formation of advection fog
• Describe the evolution of the boundary layer along an air parcel trajectory that leads to advection fog
• Describe how sea surface temperature changes along an air parcel trajectory that leads to advection fog
• Recall the origins of strong sea surface temperature gradients
• On a world map, identify areas prone to advection fog
• Recall the seasonality of advection fog

With regard to West Coast fog and low stratus:

• Describe the general synoptic environment that is conducive to fog formation
• List at least 2 ways that subtropical high-pressure systems contribute to the formation of West Coast fog and low stratus
• Describe the evolution of the boundary layer along an air parcel trajectory that leads to West Coast fog and low stratus
• List at least 2 ways that the boundary layer cools to saturation in a West Coast fog/stratus event.
• Recall the role of upwelling in the formation of West Coast fog and low stratus
• On a world map, identify areas prone to West Coast fog and low stratus
• Recall the seasonality of West Coast fog and low stratus
With regard to steam fog:
• Describe the general synoptic environment that is conducive to fog formation
• Describe the characteristics and evolution of the boundary layer along an air parcel trajectory that leads to steam fog
• On a world map, identify areas prone to steam fog
• Recall the seasonality of steam fog events

With regard to mesoscale influences upon dynamically forced fog:

• Describe the effects of coastal topography in fog formation
• Describe how coastal jets affect fog formation and dissipation
• Describe how sea breezes affect fog formation and dissipation
• Describe the impact of local variations in sea surface temperature on fog formation and dissipation

With regard to forecasting dynamically forced fog:

• Describe the general approach to forecasting fog
• List at least 4 critical atmospheric fields to monitor in plan view when forecasting fog
• List at least 4 critical atmospheric fields to monitor in vertical profiles when forecasting fog
• Describe the limitations of NWP models in fog forecasting

Estimated time to complete: 3 h

Description:
This module deals with identifying the characteristics of radiation versus advection fog events, determining which process is dominating, and applying that understanding when making ceiling and visibility forecasts. A forecast approach using a decision tree is also discussed. This decision tree outlines the basic steps involved in applying a thorough forecast approach to fog and stratus events. The module is based on live teletraining sessions offered in 2003 as part of the Distance Learning Aviation Course 1 (DLAC1) on Fog and Stratus Forecasting.

Objectives:
1. Describe the differing processes that lead to radiation fog and advection fog

2. State the two key ingredients for the formation of fog or low stratus: increasing moisture in the boundary layer or decreasing boundary layer temperatures.

3. Properly identify which processes are dominating a particular fog or low stratus event. You can do this by:

• Examining the characteristics of the processes involved,
• Examining the low-level factors that are influencing the event, and
• Comparing these to the known characteristics, processes, and factors that distinguish a radiation event from an advective event.

Estimated time to complete: 2 h

Description:
This module discusses the current theories of atmospheric conditions associated with aircraft icing and applies the theories to the icing diagnosis and forecast process. The contribution of liquid water content, temperature, and droplet size parameters to icing are examined. Identification of icing type, icing severity, and the hazards associated with icing features are presented. Tools to help diagnose atmospheric processes that may be contributing to icing and the special case of supercooled large drop (SLD) icing are examined and applied in short exercises.

The use of graphics, animations, and interactive exercises in Forecasting Aviation Icing: Icing Type and Severity helps the forecaster to gain an understanding of icing processes, to identify icing hazards, and to apply diagnosis and forecast tools as aids to evaluate and anticipate potential aircraft icing threats.

The subject matter expert for this module is Dr. Marcia Politovich of
NCAR/Research Applications Program.

This module is also available in French.

Objectives:
The goal of this training module is to help you improve your icing forecasts by

1. Becoming more familiar with the types, conditions, and hazards of aircraft icing.
2. Learning what factors determine icing type and severity, and how they interrelate.
3. Knowing what physical processes create favorable icing conditions.
4. Recognizing the types of mesoscale environments that generate such physical processes.
5. Learning some techniques to apply and patterns to look for when diagnosing data products for possible icing threats.

Performance Objectives

A. Aircraft Icing
1. Name and distinguish between the main types of in-flight aircraft icing; rank them in terms of potential hazard to aviation.
2. Describe the conditions under which the main types of in-flight aircraft icing form.
3. Name and distinguish between the four icing severity reporting categories used by pilots.

B. Icing Factors
1. Name the main factors that determine the type and severity of icing to expect in a given environment.
2. Identify ranges of values for liquid water content, temperature, and altitude that are most favorable to icing.
3. Describe the influence of droplet size on ice collection efficiency and accretion pattern.
4. Predict the most likely icing type and severity level to expect for given ranges of cloud liquid water content, temperature, and droplet size.

C. Icing Environments and Physical Processes
1. Describe the impact to icing of each of the six categories of water phase transitions.
2. Describe several of the most favorable synoptic and mesoscale environments for development of hazardous icing conditions:

• Three patterns that enhance cloud formation and hence icing potential
• Three environments that are especially conducive to supercooled large drop formation
• Two physical processes that support supercooled large drop formation
• Cloud-top conditions most favorable to supercooled large drop formation

D. Data Assessment
1. Assess the icing threat in various layers of skew T-log p diagrams.
2. Identify favorable areas and layers for supercooled large drop formation integrating:
• GOES 3.9 micron imagery
• Skew-T diagrams
• Profiler data
• WSR-88D reflectivity and velocity
• Surface precipitation observations

Estimated time to complete: 3-5 h

Description:
Forecasting Dust Storms is the latest module in the Mesoscale Meteorology Primer. The module starts by discussing the conditions required for a dust storm, including an appropriate source of dust, sufficient wind and turbulence, and an unstable atmosphere. The module then explores the fate of dust in the atmosphere including dispersion, advection, and settling. The concluding section on forecasting examines a case in the Middle East and demonstrates the use of a mesoscale NWP model, as well as next-generation dust forecasting models.

Objectives:
After completing this module, the learner should be able to do the following things:

With regard to dust storm characteristics:

• Describe how visibility varies near severe dust storms
• Recall the average height of dust storms
With regard to sources of dust:
• Describe the soil types in appropriate source regions for dust storms
• Recall that blowing dust usually does not occur for at least 24 hours after a rainfall
• Identify potential source regions with satellite imagery

With regard to atmospheric conditions required for dust storms:

• Recall the threshold wind speed for lifting fine dust particles.
• Describe the atmospheric conditions that promote lofting of dust in terms of stability and turbulence
• List the 3 ways that turbulence typically arises in the atmosphere
• Describe the effect of nightfall on dust storms

With regard to the dissipation and dispersion of dust storms:

• Describe the atmospheric factors that influence the dispersion of dust
• Describe the effect of precipitation on suspended dust and why this occurs
• Recall how quickly dust settles once winds die down

With regard to the climatology of dust storms:

• List the most common synoptic patterns for raising dust in the Middle East
• Define Shamal
• List at least 3 mesoscale weather phenomena that result in dust storms
• Describe how haboobs and dust devils originate
• Describe how winter dust storms differ from summer dust storms

With regard to the satellite detection of blowing dust:

• Describe how dust appears on IR images, during both day and night and over both land and water
• Describe how dust appears on visible images, during both day and night and over both land and water
• Describe the advantages of imagery from polar orbiting and geostationary satellites
• With regard to forecasting dust storms:
• List the tools available for observing dust storms.
• Describe how mesoscale NWP models can help with a dust storm prediciton
• List the dust storm forecasting models and describe their respective advantages

Estimated time to complete: 2 h

Description:
This is the second module in the Mesoscale Meteorology Primer series. This module starts with a forecast scenario that occurs during a winter radiation fog event in the Central Valley of California. After that, a conceptual section covers the physical processes of radiation fog through its life cycle. Operational sections addressing fog detection and forecasting conclude the module

Objectives:
At the end of the module you should be able to do the following things:

With Regard to the Preconditioning Environment:

• Identify key conditions and ingredients necessary for development of radiation fog
• Discriminate between large-scale low-level environments that are favorable and unfavorable for development of radiation fog
• Describe the sequence of key surface and boundary layer processes that prepare the low-level environment for development of radiation fog
• Demonstrate an understanding of how surface cooling dries the micro-boundary layer and prevents low-level condensation from being deposited onto the surface
• Rank various surface and surface cover types in terms of the relative speed with which low-level air in contact with them will reach saturation

With Regard to Initiation and Growth:

• Identify levels at which radiative cooling is most active at various stages of the fog initiation and growth process
• Demonstrate an understanding of the effects that various condensation nuclei types and concentrations have on fog formation
• Sequence the key processes and events that occur during formation of a layer of radiation fog
• Demonstrate an understanding of how the fog-top inversion is created by the fog itself
• Demonstrate an understanding of influences that heat flux from the surface have on a fog layer during its initiation and growth

With Regard to Maintenance Phase:

• Describe key processes that balance one another to allow a fog layer to maintain a relatively constant depth
• Identify conditions in and above a fog-top layer that support continued condensate production
• Identify conditions in and above a fog-top layer that restrict further deepening
• Demonstrate an understanding of the effects that various condensation nuclei types and concentrations have on fog maintenance
• Demonstrate an understanding of the effects that introduction of an overlying cloud layer have on a mature fog layer at the surface
• Demonstrate an understanding of influences that heat flux from the surface have on a mature fog layer
• Identify the typical level of a fog-top inversion
• Demonstrate an understanding of how the fog-top inversion is maintained by various processes at and above the top of the fog layer

With Regard to Dissipation Phase:

• Identify key processes that contribute to the dissipation of a fog layer
• Apply a droplet settling rate calculation to predict the time required for a given depth of fog layer to settle to the ground in the absence of any new condensate production
• Demonstrate an understanding of how radiative heating contributes to dissipation of a fog layer
• Demonstrate an understanding of how turbulent mixing contributes to dissipation of a fog layer
• Demonstrate an understanding of how changes in low-level winds can contribute to dissipation of a fog layer
• Demonstrate an understanding of how introduction of an overlying cloud layer can contribute to dissipation of a fog layer
With Regard to Detecting Fog:
• Identify surface observations that show atmospheric conditions conducive to radiation fog
• Identify soundings that show atmospheric conditions conducive to radiation fog
• Identify fog in satellite images
• Describe the limitations of infrared satellite images for detecting radiation fog

With Regard to Forecasting Fog:

• Describe the diurnal cycle of radiation fog occurrence
• Demonstrate and understanding of the strong seasonal dependence of radiation fog occurrence in at least two localities
• Describe which forecast products best show the atmospheric conditions conducive to radiation fog
• Describe the limitations of numerical forecast models in predicting radiation fog

Estimated time to complete: 2 h

Description:
Local and mesoscale influences can make or break your fog or stratus forecast. Influences of local water bodies, terrain, vegetation, soil characteristics, and coastal features on the lower atmosphere can play a vital role in the development, duration, and intensity of these events. As part of the Distance Learning Course 1: Forecasting Fog and Low Stratus, this module examines several of these influences and discusses how they enhance or inhibit a fog or stratus event.

Objectives:
• Identify three local factors that can enhance fog or stratus development and be able to explain why
• Identify and describe the processes external to the boundary layer that influence duration, intensity, and dissipation
• Identify and describe the processes internal to the boundary layer that influence duration, intensity, and dissipation

Estimated time to complete: 2-3 h

Description:
This is part of the Physical Processes Professional Competency Unit of the Forecasting Low-Altitude Clouds and Fog for Aviation Operations Professional Development Series. West Coast Fog discusses the climatology, physical
processes, and evolution of hot spell fogs along the U.S. West Coast.

Objectives:
The goal of this training module is to help you increase your understanding of how radiation fog forms, grows, and dissipates. Such understanding, in turn, can help you more efficiently and accurately evaluate the ability of a given atmospheric environment to generate and/or maintain radiation fog.
Performance Objectives
With Regard to Climatology
Basic Level Competencies:
• Identify coastal regions worldwide where (west coast-type) fogs occur
• For each region, state the seasons of highest and lowest frequency
With Regard to the Preconditioning Environment:
Basic Level Competencies:
• Identify typical synoptic-scale patterns associated with preconditioning processes that prepare the coastal environment for fog formation
• List low-level and sea surface conditions that are typically present prior to onset of the fog formation cycle
Advanced Level Competencies:
• Sequence key processes and events that occur during the preconditioning phase
• Demonstrate an understanding of how/why the surface inversion forms as a result of hot dry offshore winds
• Describe* how/why/where coastal upwelling occurs
With Regard to Formation:
Basic Level Competencies:
• Identify typical synoptic-scale pattern transitions associated with the formation phase
• Identify the key processes and events that occur during fog formation.
Advanced Level Competencies:
• Apply rules that describe the relationships between SST, inversion base, LCL, MCL, etc.
With Regard to Growth and Maturity:
Basic Level Competencies:
Describe the continued deepening and horizontal growth of the fog
• State the typical maximum height that the inversion can reach with cloud still extending to the surface
• Describe diurnal cycles (including stratus raising/lowering)
Advanced Level Competencies:
• Demonstrate an understanding of the roles that coastal surges can play
With Regard to Fog Dissipation and/or Stratus formation:
Basic Level Competencies:
• List processes that can result in fog dissipation (advection over land, warmer water, synoptic systems, solar radiation, the start of a new cycle)
• Identify typical synoptic-scale patterns that can destroy fog regimes in MBL
• Sequence the major events that comprise the ~15-day warm season fog cycle in this region
Advanced Level Competencies:
• Describe how the fog erodes upward to form the marine stratus regime that was present prior to fog formation
• State general rule regarding relationship between sun angle and fog dissipation through insolation
• Demonstrate an understanding of how/why dissipation occurs when the MCL reaches the base of the inversion

Estimated time to complete: 1 hr

Description:
"Writing TAFs for Winds and LLWS" is the third unit in the Distance Learning Aviation Course 2 (DLAC2) series on producing TAFs that meet the needs of the aviation community. In addition to providing information about tools for diagnosing wind and wind impacts, the module extends the Practically Perfect TAF (PPTAF) process to address airport-specific criteria. By understanding the criteria at airports for which they produce TAFs, forecasters will be better able to produce a Practically Perfect Site-Specific TAF (PPSST). The unit also examines how to effectively communicate logic and uncertainty in an aviation forecast discussion (AvnFD) and addresses maintaining an effective TAF weather watch and updating the TAF proactively.

Objectives:
* Describe the importance of accurate wind forecasts to various customers
Issue Practically Perfect TAFs that are sensitive to airport-specific criteria (i.e., PPSST—Practically Perfect Site Specific TAFs)
* Create a PPSST that meets customer needs for different airports
* Use tools, products, and data to limit uncertainty in wind and LLWS forecasts
* Use  “VRB” (Variable), “G” (Gust), and “LLWS” appropriately in a TAF
* Issue TAFs proactively and identify situations when it is best to “sit on” a TAF
* Make appropriate use of the AvnFD to express uncertainty about these phenomena
* Ensure terminal forecasts are consistent with warning, forecast, and guidance products from national aviation centers
* Demonstrate the ability to collaborate effectively when preparing a terminal forecast

Estimated time to complete: 3 h

Description:
This module discusses how to apply various observational data and remote sensing tools such as satellite, METARS, soundings, profilers, radar, and model analyses to diagnose the potential for fog and/or low stratus. Various forecast tools (such as model forecast fields, forecast soundings, and BUFKIT) used to assess fog and/or low stratus potential onset, intensity, and duration are also examined. This module is part of the Distance Learning Course 1: Forecasting Fog and Low Stratus.

Objectives:
• Apply various observational data and remote sensing tools such as satellite, METARS, soundings, profilers, radar, and model analyses to diagnose the potential for fog and/or low stratus
• Apply various forecast tools such as model forecast fields, forecast soundings, and BUFKIT to assess fog and/or low stratus potential onset, intensity, and duration

Estimated time to complete: 3 h

Description:
This module discusses the current theories of atmospheric conditions associated with aircraft icing and applies the theories to the icing diagnosis and forecast process. The contribution of liquid water content, temperature, and droplet size parameters to icing are examined. Identification of icing type, icing severity, and the hazards associated with icing features are presented. Tools to help diagnose atmospheric processes that may be contributing to icing and the special case of supercooled large drop (SLD) icing are examined and applied in short exercises.

The use of graphics, animations, and interactive exercises in Forecasting Aviation Icing: Icing Type and Severity helps the forecaster to gain an understanding of icing processes, to identify icing hazards, and to apply diagnosis and forecast tools as aids to evaluate and anticipate potential aircraft icing threats.

The subject matter expert for this module is Dr. Marcia Politovich of
NCAR/Research Applications Program.

This module is also available in French.

Objectives:
The goal of this training module is to help you improve your icing forecasts by

1. Becoming more familiar with the types, conditions, and hazards of aircraft icing.
2. Learning what factors determine icing type and severity, and how they interrelate.
3. Knowing what physical processes create favorable icing conditions.
4. Recognizing the types of mesoscale environments that generate such physical processes.
5. Learning some techniques to apply and patterns to look for when diagnosing data products for possible icing threats.

Performance Objectives

A. Aircraft Icing
1. Name and distinguish between the main types of in-flight aircraft icing; rank them in terms of potential hazard to aviation.
2. Describe the conditions under which the main types of in-flight aircraft icing form.
3. Name and distinguish between the four icing severity reporting categories used by pilots.

B. Icing Factors
1. Name the main factors that determine the type and severity of icing to expect in a given environment.
2. Identify ranges of values for liquid water content, temperature, and altitude that are most favorable to icing.
3. Describe the influence of droplet size on ice collection efficiency and accretion pattern.
4. Predict the most likely icing type and severity level to expect for given ranges of cloud liquid water content, temperature, and droplet size.

C. Icing Environments and Physical Processes
1. Describe the impact to icing of each of the six categories of water phase transitions.
2. Describe several of the most favorable synoptic and mesoscale environments for development of hazardous icing conditions:

• Three patterns that enhance cloud formation and hence icing potential
• Three environments that are especially conducive to supercooled large drop formation
• Two physical processes that support supercooled large drop formation
• Cloud-top conditions most favorable to supercooled large drop formation

D. Data Assessment
1. Assess the icing threat in various layers of skew T-log p diagrams.
2. Identify favorable areas and layers for supercooled large drop formation integrating:
• GOES 3.9 micron imagery
• Skew-T diagrams
• Profiler data
• WSR-88D reflectivity and velocity
• Surface precipitation observations

Estimated time to complete: 3-5 h

Description:
Forecasting Dust Storms is the latest module in the Mesoscale Meteorology Primer. The module starts by discussing the conditions required for a dust storm, including an appropriate source of dust, sufficient wind and turbulence, and an unstable atmosphere. The module then explores the fate of dust in the atmosphere including dispersion, advection, and settling. The concluding section on forecasting examines a case in the Middle East and demonstrates the use of a mesoscale NWP model, as well as next-generation dust forecasting models.

Objectives:
After completing this module, the learner should be able to do the following things:

With regard to dust storm characteristics:

• Describe how visibility varies near severe dust storms
• Recall the average height of dust storms
With regard to sources of dust:
• Describe the soil types in appropriate source regions for dust storms
• Recall that blowing dust usually does not occur for at least 24 hours after a rainfall
• Identify potential source regions with satellite imagery

With regard to atmospheric conditions required for dust storms:

• Recall the threshold wind speed for lifting fine dust particles.
• Describe the atmospheric conditions that promote lofting of dust in terms of stability and turbulence
• List the 3 ways that turbulence typically arises in the atmosphere
• Describe the effect of nightfall on dust storms

With regard to the dissipation and dispersion of dust storms:

• Describe the atmospheric factors that influence the dispersion of dust
• Describe the effect of precipitation on suspended dust and why this occurs
• Recall how quickly dust settles once winds die down

With regard to the climatology of dust storms:

• List the most common synoptic patterns for raising dust in the Middle East
• Define Shamal
• List at least 3 mesoscale weather phenomena that result in dust storms
• Describe how haboobs and dust devils originate
• Describe how winter dust storms differ from summer dust storms

With regard to the satellite detection of blowing dust:

• Describe how dust appears on IR images, during both day and night and over both land and water
• Describe how dust appears on visible images, during both day and night and over both land and water
• Describe the advantages of imagery from polar orbiting and geostationary satellites
• With regard to forecasting dust storms:
• List the tools available for observing dust storms.
• Describe how mesoscale NWP models can help with a dust storm prediciton
• List the dust storm forecasting models and describe their respective advantages

Estimated time to complete: 2 h

Description:
This is the second module in the Mesoscale Meteorology Primer series. This module starts with a forecast scenario that occurs during a winter radiation fog event in the Central Valley of California. After that, a conceptual section covers the physical processes of radiation fog through its life cycle. Operational sections addressing fog detection and forecasting conclude the module

Objectives:
At the end of the module you should be able to do the following things:

With Regard to the Preconditioning Environment:

• Identify key conditions and ingredients necessary for development of radiation fog
• Discriminate between large-scale low-level environments that are favorable and unfavorable for development of radiation fog
• Describe the sequence of key surface and boundary layer processes that prepare the low-level environment for development of radiation fog
• Demonstrate an understanding of how surface cooling dries the micro-boundary layer and prevents low-level condensation from being deposited onto the surface
• Rank various surface and surface cover types in terms of the relative speed with which low-level air in contact with them will reach saturation

With Regard to Initiation and Growth:

• Identify levels at which radiative cooling is most active at various stages of the fog initiation and growth process
• Demonstrate an understanding of the effects that various condensation nuclei types and concentrations have on fog formation
• Sequence the key processes and events that occur during formation of a layer of radiation fog
• Demonstrate an understanding of how the fog-top inversion is created by the fog itself
• Demonstrate an understanding of influences that heat flux from the surface have on a fog layer during its initiation and growth

With Regard to Maintenance Phase:

• Describe key processes that balance one another to allow a fog layer to maintain a relatively constant depth
• Identify conditions in and above a fog-top layer that support continued condensate production
• Identify conditions in and above a fog-top layer that restrict further deepening
• Demonstrate an understanding of the effects that various condensation nuclei types and concentrations have on fog maintenance
• Demonstrate an understanding of the effects that introduction of an overlying cloud layer have on a mature fog layer at the surface
• Demonstrate an understanding of influences that heat flux from the surface have on a mature fog layer
• Identify the typical level of a fog-top inversion
• Demonstrate an understanding of how the fog-top inversion is maintained by various processes at and above the top of the fog layer

With Regard to Dissipation Phase:

• Identify key processes that contribute to the dissipation of a fog layer
• Apply a droplet settling rate calculation to predict the time required for a given depth of fog layer to settle to the ground in the absence of any new condensate production
• Demonstrate an understanding of how radiative heating contributes to dissipation of a fog layer
• Demonstrate an understanding of how turbulent mixing contributes to dissipation of a fog layer
• Demonstrate an understanding of how changes in low-level winds can contribute to dissipation of a fog layer
• Demonstrate an understanding of how introduction of an overlying cloud layer can contribute to dissipation of a fog layer
With Regard to Detecting Fog:
• Identify surface observations that show atmospheric conditions conducive to radiation fog
• Identify soundings that show atmospheric conditions conducive to radiation fog
• Identify fog in satellite images
• Describe the limitations of infrared satellite images for detecting radiation fog

With Regard to Forecasting Fog:

• Describe the diurnal cycle of radiation fog occurrence
• Demonstrate and understanding of the strong seasonal dependence of radiation fog occurrence in at least two localities
• Describe which forecast products best show the atmospheric conditions conducive to radiation fog
• Describe the limitations of numerical forecast models in predicting radiation fog

Estimated time to complete: 2 h

Description:
Meteorologists typically examine atmospheric soundings in the course of preparing a weather forecast. The skew-T / log-P diagram provides the preferred method for analyzing these soundings. This module comprehensively examines the use of the skew-T diagram. It explores thermodynamic properties, convective parameters, stability assessment, and several forecast applications. The module is designed for both instruction and reference. It also comes with an interactive Web-based skew-T diagram that calculates several common forecast parameters.

Objectives:
Module Goal
The goal of this module is to teach the novice forecaster to effectively use the skew-T/log-P diagram. After completing the module, they should be able to read and interpret a sounding plotted on a skew-T/log P diagram and apply that information to a weather forecast.

Performance Objectives

1. Given a skew-T/log-P diagram, identify and describe the various lines.


2. Given a sounding plotted on a skew-T/log-P diagram:




• Read or calculate the thermodynamic properties at various levels.


• Determine the convective levels, including the LCL, CCL, LFC, MCL, EL, and MPL.


• Determine stability indices such as LI, SSI, KI, TT, and SWEAT and use them to assess the potential for severe weather.




3. Describe how CAPE and CIN are determined.


4. List and describe the different types of stability and identify them in a sounding plotted on a skew-T diagram


5. List and describe the different types of lapse rates and relate them to stability.


6. List and describe processes that alter stability and give examples of common cases where those processes occur.


7. Given a suitable synoptic environment and a sounding plotted on a skew-T/log-P diagram, interpret the sounding with regard to common forecast problems.

Estimated time to complete: 6-8 h

Description:
"Writing TAFs for Winds and LLWS" is the third unit in the Distance Learning Aviation Course 2 (DLAC2) series on producing TAFs that meet the needs of the aviation community. In addition to providing information about tools for diagnosing wind and wind impacts, the module extends the Practically Perfect TAF (PPTAF) process to address airport-specific criteria. By understanding the criteria at airports for which they produce TAFs, forecasters will be better able to produce a Practically Perfect Site-Specific TAF (PPSST). The unit also examines how to effectively communicate logic and uncertainty in an aviation forecast discussion (AvnFD) and addresses maintaining an effective TAF weather watch and updating the TAF proactively.

Objectives:
* Describe the importance of accurate wind forecasts to various customers
Issue Practically Perfect TAFs that are sensitive to airport-specific criteria (i.e., PPSST—Practically Perfect Site Specific TAFs)
* Create a PPSST that meets customer needs for different airports
* Use tools, products, and data to limit uncertainty in wind and LLWS forecasts
* Use  “VRB” (Variable), “G” (Gust), and “LLWS” appropriately in a TAF
* Issue TAFs proactively and identify situations when it is best to “sit on” a TAF
* Make appropriate use of the AvnFD to express uncertainty about these phenomena
* Ensure terminal forecasts are consistent with warning, forecast, and guidance products from national aviation centers
* Demonstrate the ability to collaborate effectively when preparing a terminal forecast

Estimated time to complete: 3 h

Description:
This module discusses how to apply various observational data and remote sensing tools such as satellite, METARS, soundings, profilers, radar, and model analyses to diagnose the potential for fog and/or low stratus. Various forecast tools (such as model forecast fields, forecast soundings, and BUFKIT) used to assess fog and/or low stratus potential onset, intensity, and duration are also examined. This module is part of the Distance Learning Course 1: Forecasting Fog and Low Stratus.

Objectives:
• Apply various observational data and remote sensing tools such as satellite, METARS, soundings, profilers, radar, and model analyses to diagnose the potential for fog and/or low stratus
• Apply various forecast tools such as model forecast fields, forecast soundings, and BUFKIT to assess fog and/or low stratus potential onset, intensity, and duration

Estimated time to complete: 3 h

Description:
In this Southern Hemisphere-focused module, the student can work through one major Australian severe thunderstorm event in detail and examine aspects of two other severe thunderstorm events as well. Follow a forecast time-line to assess data and make decisions from the pre-storm phase through the warning phase.



NOTE: The Bureau of Meteorology owns this module, NOT the COMET Program.

Estimated time to complete: 4-6 h

Description:
“Basic Terminal Forecast Strategies” is the first component of the Distance Learning Course 2, Producing Customer-Focused TAFs. Basic Terminal Forecast Strategies is comprised of two lessons that provide 1) an introduction to understanding aviation customers and their needs and 2) a technique to meet those needs by producing clear, concise, and consistent terminal aerodrome forecasts (TAFs).

Objectives:
1. Identify aviation customer groups and describe how they use TAFs.
2. Recognize common terminal forecast problems that adversely impact customers.
3. Analyze TAFs to determine which would be considered "good" or "poor" by customers.
4. Describe how overuse of conditional terms (e.g., TEMPO) lowers forecast verification scores and impedes effective customer decision-making.
5. Describe the relationship between aviation verification scores and customer satisfaction.
6. Create a Practically Perfect TAF (PP TAF) that meets common customer needs.

Estimated time to complete: 2 h

Description:
Mountain waves form above and downwind of topographic barriers and frequently pose a serious hazard to mountain aviation because of strong-to-extreme turbulence. This foundation module describes the features of mountain waves and explores the conditions under which they form. Like other foundation modules in the Mesoscale Primer, this module starts with a forecast scenario and concludes with a final exam. Rich graphics, audio narration, and frequent interactions enhance the presentation.

Objectives:
After completing this module, the learner should be able to do the following things.

With regard to the hazards, features, and climatology of mountain waves and downslope winds:

* Identify at least 2 hazards associated with mountain wave activity
* Recall at least 3 atmospheric and topographic requirements for a mountain wave system
* Describe the major features of a mountain wave system
* Recall when and where mountain waves and downslope winds occur
* Recall the location of the following winds: Chinook, Santa Ana, Bora, and Foehn

With regard to downslope winds:

* Recall characteristics of downslope winds
* Describe why downslope winds are warm

With regard to the origin of mountain waves and downslope winds:

* Describe why air displaced over a mountain range starts to oscillate
* Recall the conditions that lead to topographically-blocked flow in terms of mountain height, wind speed, stability, and Froude number
* Describe the effects of wind shear and inversions on mountain wave activity
* Define critical level
* Discriminate between a self-induced critical level and a mean-state critical level
* Describe the different types of rotors and their associated atmospheric conditions
* Identify which type of rotor is associated with more turbulence

With regard to forecasting mountain waves and downslope winds:

* Recall the 1.6 rule-of-thumb
* Recall what NWP model resolution is required to accurately depict mountain waves
* Describe how a model's vertical coordinate system affects its ability to forecast mountain waves
* Describe how radiosondes and pilot reports (PIREPs) can help with short-range forecasting of mountain waves
* Describe how satellite imagery can be used to detect mountain wave activity with or without either daylight or clouds

Estimated time to complete: 2-3 h

Description:
This module describes the phenomena of the sea breeze. It examines factors that lead to the formation of a sea breeze, modifying effects on sea breeze development, how mesoscale NWP models handle sea breezes, and sea breeze forecast parameters. The module places instruction in the context of a sea breeze case from Florida and compares surface and satellite observations to a model simulation using the AFWA MM5. Like other modules in the Mesoscale Meteorology Primer, this module comes with audio narration, rich graphics, and a companion print version.

Objectives:
Terminal Objectives
By the end of this module you will be able to describe how and why, when and where sea breezes occur

Enabling Objectives
By the end of this module you will be able to do the following:
1. Describe when and where sea breezes form
2. Characterize the sea breeze in terms of strength and horizontal and vertical extent
3. List the principle factors that affect sea breeze formation
4. List the sensible weather associated with formation and passage of a sea breeze front
5. Describe the use and limitations of NWP model simulations of sea breezes.
6. Describe how satellite imagery can assist in detecting sea breezes

Estimated time to complete: 1 h

Description:
This module provides an overview of some of the applicable TAF Amendment and Conditional Group usage rules, as presented in the latest version of the National Weather Service Instruction 10-813 on TAF directives. It also presents a methodology for TAF writing and development that will lead to an effective and user-friendly product. The focus is on the ceiling and visibility aspects of the TAF. This module is part of the Distance Learning Course 1: Forecasting Fog and Low Stratus.

Objectives:
• Develop an understanding and appreciation for how TAF construction (intelligent vs. excessive use of TEMPO and PROB groups) may impact your aviation customers
• Develop skills in writing an effective “practical” TAF that provides an improved forecast of expected flight category changes, while maintaining a customer-friendly format. Compare effective vs. poor TAF structures for a given scenario
• Develop concise TAFs with sparing use of change or conditional groups such as TEMPO and PROB, as we’ll practice in two small case exercises

Estimated time to complete: 2 h

Description:
"Writing TAFs for Convective Weather" uses a case to show how special tools and techniques can be used to produce a Practically Perfect TAF (PPTAF) for convection. The unit examines how to create TAFs for different types of convection and how to effectively communicate logic and uncertainty in an aviation forecast discussion (AvnFD) or by other means. It also addresses maintaining an effective TAF weather watch and updating the TAF proactively.

Objectives:
1. Describe how general convective hazards might impact airport operations.
2. Describe how the unique characteristics of each convective type relate to creating a TAF.
3. List the strengths and weaknesses of using BUFKIT, aircraft weather data, AWIPS Time-of-Arrival (TOA)/Lead Time and Time Series tools, satellite data, climatology, and other special tools for creating a TAF for convection.
4. Explain why the PPTAF procedure needs to be revised for convection and why the use of special tools is so important for this process.
5. Produce a PPTAF for a mesoscale convective system, air mass thunderstorms, supercell thunderstorms, or microbursts
6. Effectively articulate forecast logic and uncertainty about a TAF in an Aviation Forecast Discussion (AvnFD).
7. Ensure a TAF is consistent with previous TAFs or other products issued by both local offices and national centers.
8. Be able to run an effective weather watch by identifying beforehand when a TAF update is warranted.
9. Show the ability to update proactively, rather than in a reactive fashion.
10. Identify when coordination is necessary for the TAF and with whom it should be conducted.

Estimated time to complete: 2 h

Description:
"Writing TAFs for Winds and LLWS" is the third unit in the Distance Learning Aviation Course 2 (DLAC2) series on producing TAFs that meet the needs of the aviation community. In addition to providing information about tools for diagnosing wind and wind impacts, the module extends the Practically Perfect TAF (PPTAF) process to address airport-specific criteria. By understanding the criteria at airports for which they produce TAFs, forecasters will be better able to produce a Practically Perfect Site-Specific TAF (PPSST). The unit also examines how to effectively communicate logic and uncertainty in an aviation forecast discussion (AvnFD) and addresses maintaining an effective TAF weather watch and updating the TAF proactively.

Objectives:
* Describe the importance of accurate wind forecasts to various customers
Issue Practically Perfect TAFs that are sensitive to airport-specific criteria (i.e., PPSST—Practically Perfect Site Specific TAFs)
* Create a PPSST that meets customer needs for different airports
* Use tools, products, and data to limit uncertainty in wind and LLWS forecasts
* Use  “VRB” (Variable), “G” (Gust), and “LLWS” appropriately in a TAF
* Issue TAFs proactively and identify situations when it is best to “sit on” a TAF
* Make appropriate use of the AvnFD to express uncertainty about these phenomena
* Ensure terminal forecasts are consistent with warning, forecast, and guidance products from national aviation centers
* Demonstrate the ability to collaborate effectively when preparing a terminal forecast

Estimated time to complete: 3 h

Description:
This module discusses how to apply various observational data and remote sensing tools such as satellite, METARS, soundings, profilers, radar, and model analyses to diagnose the potential for fog and/or low stratus. Various forecast tools (such as model forecast fields, forecast soundings, and BUFKIT) used to assess fog and/or low stratus potential onset, intensity, and duration are also examined. This module is part of the Distance Learning Course 1: Forecasting Fog and Low Stratus.

Objectives:
• Apply various observational data and remote sensing tools such as satellite, METARS, soundings, profilers, radar, and model analyses to diagnose the potential for fog and/or low stratus
• Apply various forecast tools such as model forecast fields, forecast soundings, and BUFKIT to assess fog and/or low stratus potential onset, intensity, and duration

Estimated time to complete: 3 h

Description:
This is the second module in the Mesoscale Meteorology Primer series. This module starts with a forecast scenario that occurs during a winter radiation fog event in the Central Valley of California. After that, a conceptual section covers the physical processes of radiation fog through its life cycle. Operational sections addressing fog detection and forecasting conclude the module

Objectives:
At the end of the module you should be able to do the following things:

With Regard to the Preconditioning Environment:

• Identify key conditions and ingredients necessary for development of radiation fog
• Discriminate between large-scale low-level environments that are favorable and unfavorable for development of radiation fog
• Describe the sequence of key surface and boundary layer processes that prepare the low-level environment for development of radiation fog
• Demonstrate an understanding of how surface cooling dries the micro-boundary layer and prevents low-level condensation from being deposited onto the surface
• Rank various surface and surface cover types in terms of the relative speed with which low-level air in contact with them will reach saturation

With Regard to Initiation and Growth:

• Identify levels at which radiative cooling is most active at various stages of the fog initiation and growth process
• Demonstrate an understanding of the effects that various condensation nuclei types and concentrations have on fog formation
• Sequence the key processes and events that occur during formation of a layer of radiation fog
• Demonstrate an understanding of how the fog-top inversion is created by the fog itself
• Demonstrate an understanding of influences that heat flux from the surface have on a fog layer during its initiation and growth

With Regard to Maintenance Phase:

• Describe key processes that balance one another to allow a fog layer to maintain a relatively constant depth
• Identify conditions in and above a fog-top layer that support continued condensate production
• Identify conditions in and above a fog-top layer that restrict further deepening
• Demonstrate an understanding of the effects that various condensation nuclei types and concentrations have on fog maintenance
• Demonstrate an understanding of the effects that introduction of an overlying cloud layer have on a mature fog layer at the surface
• Demonstrate an understanding of influences that heat flux from the surface have on a mature fog layer
• Identify the typical level of a fog-top inversion
• Demonstrate an understanding of how the fog-top inversion is maintained by various processes at and above the top of the fog layer

With Regard to Dissipation Phase:

• Identify key processes that contribute to the dissipation of a fog layer
• Apply a droplet settling rate calculation to predict the time required for a given depth of fog layer to settle to the ground in the absence of any new condensate production
• Demonstrate an understanding of how radiative heating contributes to dissipation of a fog layer
• Demonstrate an understanding of how turbulent mixing contributes to dissipation of a fog layer
• Demonstrate an understanding of how changes in low-level winds can contribute to dissipation of a fog layer
• Demonstrate an understanding of how introduction of an overlying cloud layer can contribute to dissipation of a fog layer
With Regard to Detecting Fog:
• Identify surface observations that show atmospheric conditions conducive to radiation fog
• Identify soundings that show atmospheric conditions conducive to radiation fog
• Identify fog in satellite images
• Describe the limitations of infrared satellite images for detecting radiation fog

With Regard to Forecasting Fog:

• Describe the diurnal cycle of radiation fog occurrence
• Demonstrate and understanding of the strong seasonal dependence of radiation fog occurrence in at least two localities
• Describe which forecast products best show the atmospheric conditions conducive to radiation fog
• Describe the limitations of numerical forecast models in predicting radiation fog

Estimated time to complete: 2 h

Description:
Mountain waves form above and downwind of topographic barriers and frequently pose a serious hazard to mountain aviation because of strong-to-extreme turbulence. This foundation module describes the features of mountain waves and explores the conditions under which they form. Like other foundation modules in the Mesoscale Primer, this module starts with a forecast scenario and concludes with a final exam. Rich graphics, audio narration, and frequent interactions enhance the presentation.

Objectives:
After completing this module, the learner should be able to do the following things.

With regard to the hazards, features, and climatology of mountain waves and downslope winds:

* Identify at least 2 hazards associated with mountain wave activity
* Recall at least 3 atmospheric and topographic requirements for a mountain wave system
* Describe the major features of a mountain wave system
* Recall when and where mountain waves and downslope winds occur
* Recall the location of the following winds: Chinook, Santa Ana, Bora, and Foehn

With regard to downslope winds:

* Recall characteristics of downslope winds
* Describe why downslope winds are warm

With regard to the origin of mountain waves and downslope winds:

* Describe why air displaced over a mountain range starts to oscillate
* Recall the conditions that lead to topographically-blocked flow in terms of mountain height, wind speed, stability, and Froude number
* Describe the effects of wind shear and inversions on mountain wave activity
* Define critical level
* Discriminate between a self-induced critical level and a mean-state critical level
* Describe the different types of rotors and their associated atmospheric conditions
* Identify which type of rotor is associated with more turbulence

With regard to forecasting mountain waves and downslope winds:

* Recall the 1.6 rule-of-thumb
* Recall what NWP model resolution is required to accurately depict mountain waves
* Describe how a model's vertical coordinate system affects its ability to forecast mountain waves
* Describe how radiosondes and pilot reports (PIREPs) can help with short-range forecasting of mountain waves
* Describe how satellite imagery can be used to detect mountain wave activity with or without either daylight or clouds

Estimated time to complete: 2-3 h

Description:
This is part of the Physical Processes Professional Competency Unit of the Forecasting Low-Altitude Clouds and Fog for Aviation Operations Professional Development Series. West Coast Fog discusses the climatology, physical
processes, and evolution of hot spell fogs along the U.S. West Coast.

Objectives:
The goal of this training module is to help you increase your understanding of how radiation fog forms, grows, and dissipates. Such understanding, in turn, can help you more efficiently and accurately evaluate the ability of a given atmospheric environment to generate and/or maintain radiation fog.
Performance Objectives
With Regard to Climatology
Basic Level Competencies:
• Identify coastal regions worldwide where (west coast-type) fogs occur
• For each region, state the seasons of highest and lowest frequency
With Regard to the Preconditioning Environment:
Basic Level Competencies:
• Identify typical synoptic-scale patterns associated with preconditioning processes that prepare the coastal environment for fog formation
• List low-level and sea surface conditions that are typically present prior to onset of the fog formation cycle
Advanced Level Competencies:
• Sequence key processes and events that occur during the preconditioning phase
• Demonstrate an understanding of how/why the surface inversion forms as a result of hot dry offshore winds
• Describe* how/why/where coastal upwelling occurs
With Regard to Formation:
Basic Level Competencies:
• Identify typical synoptic-scale pattern transitions associated with the formation phase
• Identify the key processes and events that occur during fog formation.
Advanced Level Competencies:
• Apply rules that describe the relationships between SST, inversion base, LCL, MCL, etc.
With Regard to Growth and Maturity:
Basic Level Competencies:
Describe the continued deepening and horizontal growth of the fog
• State the typical maximum height that the inversion can reach with cloud still extending to the surface
• Describe diurnal cycles (including stratus raising/lowering)
Advanced Level Competencies:
• Demonstrate an understanding of the roles that coastal surges can play
With Regard to Fog Dissipation and/or Stratus formation:
Basic Level Competencies:
• List processes that can result in fog dissipation (advection over land, warmer water, synoptic systems, solar radiation, the start of a new cycle)
• Identify typical synoptic-scale patterns that can destroy fog regimes in MBL
• Sequence the major events that comprise the ~15-day warm season fog cycle in this region
Advanced Level Competencies:
• Describe how the fog erodes upward to form the marine stratus regime that was present prior to fog formation
• State general rule regarding relationship between sun angle and fog dissipation through insolation
• Demonstrate an understanding of how/why dissipation occurs when the MCL reaches the base of the inversion

Estimated time to complete: 1 hr

Description:
This module discusses how to apply various observational data and remote sensing tools such as satellite, METARS, soundings, profilers, radar, and model analyses to diagnose the potential for fog and/or low stratus. Various forecast tools (such as model forecast fields, forecast soundings, and BUFKIT) used to assess fog and/or low stratus potential onset, intensity, and duration are also examined. This module is part of the Distance Learning Course 1: Forecasting Fog and Low Stratus.

Objectives:
• Apply various observational data and remote sensing tools such as satellite, METARS, soundings, profilers, radar, and model analyses to diagnose the potential for fog and/or low stratus
• Apply various forecast tools such as model forecast fields, forecast soundings, and BUFKIT to assess fog and/or low stratus potential onset, intensity, and duration

Estimated time to complete: 3 h

Description:
In this Southern Hemisphere-focused module, the student can work through one major Australian severe thunderstorm event in detail and examine aspects of two other severe thunderstorm events as well. Follow a forecast time-line to assess data and make decisions from the pre-storm phase through the warning phase.



NOTE: The Bureau of Meteorology owns this module, NOT the COMET Program.

Estimated time to complete: 4-6 h

Description:
Fog frequently forms in response to dynamically forced changes in the boundary layer. This module examines dynamically forced fog in the coastal and marine environment, focusing on advection fog, steam fog, and west coast type fog. The focus of the module is on the boundary layer evolution of air parcels as they traverse trajectories over land and water. The module also examines mesoscale effects that impact the distribution of fog and low-level stratus over short distances. A general discussion of forecast products and methodologies concludes the module.

Objectives:
After completing this module, the learner should be able to do the following things:

With regard to the general features of dynamically forced fog and stratus:

• Describe the differences in boundary layer characteristics and evolution for advection, West Coast, and steam fog in a marine environment
• Describe the differences in synoptic environments for advection, West Coast, and steam fog in a marine environment
• Describe the relationship of sea surface temperature to fog formation for advection, West Coast, and steam fog in a marine environment
With regard to advection fog:
• Describe the general synoptic environment that is conducive to fog formation
• List at least 2 ways that subtropical high-pressure systems contribute to the formation of advection fog
• Describe the evolution of the boundary layer along an air parcel trajectory that leads to advection fog
• Describe how sea surface temperature changes along an air parcel trajectory that leads to advection fog
• Recall the origins of strong sea surface temperature gradients
• On a world map, identify areas prone to advection fog
• Recall the seasonality of advection fog

With regard to West Coast fog and low stratus:

• Describe the general synoptic environment that is conducive to fog formation
• List at least 2 ways that subtropical high-pressure systems contribute to the formation of West Coast fog and low stratus
• Describe the evolution of the boundary layer along an air parcel trajectory that leads to West Coast fog and low stratus
• List at least 2 ways that the boundary layer cools to saturation in a West Coast fog/stratus event.
• Recall the role of upwelling in the formation of West Coast fog and low stratus
• On a world map, identify areas prone to West Coast fog and low stratus
• Recall the seasonality of West Coast fog and low stratus
With regard to steam fog:
• Describe the general synoptic environment that is conducive to fog formation
• Describe the characteristics and evolution of the boundary layer along an air parcel trajectory that leads to steam fog
• On a world map, identify areas prone to steam fog
• Recall the seasonality of steam fog events

With regard to mesoscale influences upon dynamically forced fog:

• Describe the effects of coastal topography in fog formation
• Describe how coastal jets affect fog formation and dissipation
• Describe how sea breezes affect fog formation and dissipation
• Describe the impact of local variations in sea surface temperature on fog formation and dissipation

With regard to forecasting dynamically forced fog:

• Describe the general approach to forecasting fog
• List at least 4 critical atmospheric fields to monitor in plan view when forecasting fog
• List at least 4 critical atmospheric fields to monitor in vertical profiles when forecasting fog
• Describe the limitations of NWP models in fog forecasting

Estimated time to complete: 3 h

Description:
This module deals with identifying the characteristics of radiation versus advection fog events, determining which process is dominating, and applying that understanding when making ceiling and visibility forecasts. A forecast approach using a decision tree is also discussed. This decision tree outlines the basic steps involved in applying a thorough forecast approach to fog and stratus events. The module is based on live teletraining sessions offered in 2003 as part of the Distance Learning Aviation Course 1 (DLAC1) on Fog and Stratus Forecasting.

Objectives:
1. Describe the differing processes that lead to radiation fog and advection fog

2. State the two key ingredients for the formation of fog or low stratus: increasing moisture in the boundary layer or decreasing boundary layer temperatures.

3. Properly identify which processes are dominating a particular fog or low stratus event. You can do this by:

• Examining the characteristics of the processes involved,
• Examining the low-level factors that are influencing the event, and
• Comparing these to the known characteristics, processes, and factors that distinguish a radiation event from an advective event.

Estimated time to complete: 2 h

Description:
Forecasting Dust Storms is the latest module in the Mesoscale Meteorology Primer. The module starts by discussing the conditions required for a dust storm, including an appropriate source of dust, sufficient wind and turbulence, and an unstable atmosphere. The module then explores the fate of dust in the atmosphere including dispersion, advection, and settling. The concluding section on forecasting examines a case in the Middle East and demonstrates the use of a mesoscale NWP model, as well as next-generation dust forecasting models.

Objectives:
After completing this module, the learner should be able to do the following things:

With regard to dust storm characteristics:

• Describe how visibility varies near severe dust storms
• Recall the average height of dust storms
With regard to sources of dust:
• Describe the soil types in appropriate source regions for dust storms
• Recall that blowing dust usually does not occur for at least 24 hours after a rainfall
• Identify potential source regions with satellite imagery

With regard to atmospheric conditions required for dust storms:

• Recall the threshold wind speed for lifting fine dust particles.
• Describe the atmospheric conditions that promote lofting of dust in terms of stability and turbulence
• List the 3 ways that turbulence typically arises in the atmosphere
• Describe the effect of nightfall on dust storms

With regard to the dissipation and dispersion of dust storms:

• Describe the atmospheric factors that influence the dispersion of dust
• Describe the effect of precipitation on suspended dust and why this occurs
• Recall how quickly dust settles once winds die down

With regard to the climatology of dust storms:

• List the most common synoptic patterns for raising dust in the Middle East
• Define Shamal
• List at least 3 mesoscale weather phenomena that result in dust storms
• Describe how haboobs and dust devils originate
• Describe how winter dust storms differ from summer dust storms

With regard to the satellite detection of blowing dust:

• Describe how dust appears on IR images, during both day and night and over both land and water
• Describe how dust appears on visible images, during both day and night and over both land and water
• Describe the advantages of imagery from polar orbiting and geostationary satellites
• With regard to forecasting dust storms:
• List the tools available for observing dust storms.
• Describe how mesoscale NWP models can help with a dust storm prediciton
• List the dust storm forecasting models and describe their respective advantages

Estimated time to complete: 2 h

Description:
This module provides a basic understanding of why gap winds occur, their typical structures, and how gap wind strength and extent are controlled by larger-scale, or synoptic, conditions. You will learn about a number of important gap flows in coastal regions around the world, with special attention given to comprehensively documented gap wind cases in the Strait of Juan de Fuca and the Columbia River Gorge. Basic techniques for evaluating and predicting gap flows are presented. The module reviews the capabilities and limitations of the current generation of mesoscale models in producing realistic gap winds. By the end of this module, you should have sufficient background to diagnose and forecast gap flows around the world, and to use this knowledge to understand their implications for operational decisions. Other features in this module include a concise summary for quick reference and a final exam to test your knowledge. Like other modules in the Mesoscale Meteorology Primer, this module comes with audio narration, rich graphics, and a companion print version.

Objectives:
After completing this module, the learner should be able to do the following:

With regard to the description of gap winds:
• Recall where in a gap the strongest wind speeds are typically observed.
• Describe the different kinds of topographic gaps and their effect on gap flow.
• List at least 3 natural hazards that may be associated with gap winds.

With regard to the structure of gap winds:
• Describe how wind speed varies through the gap during a gap flow event.
• Describe the temperature profile through a gap during a gap flow event.
• Describe the pressure profile through a gap during a gap flow event.

With regard to the origin of gap flows:
• Describe the conditions required for geostrophic flow.
• Recall that gap winds are typically non-geostrophic.
• Describe the origin of the pressure gradients that occur across gaps.
• Recall that the thinning of low-level cool air at a gap exit can increase the pressure gradient across a gap.
• Recall that adiabatic warming of downslope winds can increase the pressure gradient across a gap.

With regard to forecasting gap winds:
• Qualitatively describe how varying the following factors affects wind speed through a gap:
   * Pressure gradient
   * Surface roughness
   * Gap length
   * Temperature
• Describe the horizontal resolution of a mesoscale model required to accurately forecast flow through a gap.

Estimated time to complete: 1.5-2 h

Description:
Local and mesoscale influences can make or break your fog or stratus forecast. Influences of local water bodies, terrain, vegetation, soil characteristics, and coastal features on the lower atmosphere can play a vital role in the development, duration, and intensity of these events. As part of the Distance Learning Course 1: Forecasting Fog and Low Stratus, this module examines several of these influences and discusses how they enhance or inhibit a fog or stratus event.

Objectives:
• Identify three local factors that can enhance fog or stratus development and be able to explain why
• Identify and describe the processes external to the boundary layer that influence duration, intensity, and dissipation
• Identify and describe the processes internal to the boundary layer that influence duration, intensity, and dissipation

Estimated time to complete: 2-3 h

Description:
This module provides a brief overview of Buoyancy and CAPE. Topics covered include the origin of atmospheric buoyancy, estimating buoyancy using the CAPE and Lifted Index, factors that affect buoyancy including entrainment of mid-level air, water loading, convective inhibition, and the origin of convective downdrafts. This module delivers instruction with audio narration, rich graphics, and a companion print version.

Objectives:
Terminal Objectives
By the end of this module you will be able to do the following:
1. Describe how buoyancy contributes to formation of a convective storm and its related updrafts and downdrafts
2. Define CAPE, LI, and CIN and describe how they can be used to forecast convective activity

Enabling Objectives
By the end of this module you will be able to do the following:
1. Define buoyancy and list factors that tend to increase buoyancy
2. Describe the life cycle of a convective storm
3. Define CAPE and describe how CAPE is determined on a skew-T/log-P diagram
4. Define Lifted Index (LI) and describe how LI is determined on a skew-T/log-P diagram
5. Describe how CAPE differs from Lifted Index
6. Define Convective Inhibition (CIN) and list factors that tend to increase CIN
7. Given 2 soundings, choose the soundings that will give the stronger updraft or downdraft

Estimated time to complete: 1 h

Description:
This module provides a basic understanding of how to plot and interpret hodographs, with application to convective environments. Most of the material previously appeared in the CD module, Anticipating Convective Storm Structure and Evolution, developed with Dr. Morris Weisman. Principles of Convection II: Using Hodographs includes a concise summary for quick reference and a final exam to test your knowledge. The module comes with audio narration, rich graphics, and a companion print version.

Objectives:
Terminal Objectives
1. By the end of this module you will be able to plot and use a hodograph to determine wind shear

Enabling Objectives
By the end of this module you will be able to do the following:
1. Given a vertical profile of wind speed and direction, plot a hodograph on a polar coordinate chart
2. Describe how to use a hodograph to determine the vertical wind shear between two levels
3. Given a hodograph, determine the total magnitude of vertical wind shear, the mean shear direction, and the mean wind and storm motion from a hodograph

Estimated time to complete: 60 min

Description:
Meteorologists typically examine atmospheric soundings in the course of preparing a weather forecast. The skew-T / log-P diagram provides the preferred method for analyzing these soundings. This module comprehensively examines the use of the skew-T diagram. It explores thermodynamic properties, convective parameters, stability assessment, and several forecast applications. The module is designed for both instruction and reference. It also comes with an interactive Web-based skew-T diagram that calculates several common forecast parameters.

Objectives:
Module Goal
The goal of this module is to teach the novice forecaster to effectively use the skew-T/log-P diagram. After completing the module, they should be able to read and interpret a sounding plotted on a skew-T/log P diagram and apply that information to a weather forecast.

Performance Objectives

1. Given a skew-T/log-P diagram, identify and describe the various lines.


2. Given a sounding plotted on a skew-T/log-P diagram:




• Read or calculate the thermodynamic properties at various levels.


• Determine the convective levels, including the LCL, CCL, LFC, MCL, EL, and MPL.


• Determine stability indices such as LI, SSI, KI, TT, and SWEAT and use them to assess the potential for severe weather.




3. Describe how CAPE and CIN are determined.


4. List and describe the different types of stability and identify them in a sounding plotted on a skew-T diagram


5. List and describe the different types of lapse rates and relate them to stability.


6. List and describe processes that alter stability and give examples of common cases where those processes occur.


7. Given a suitable synoptic environment and a sounding plotted on a skew-T/log-P diagram, interpret the sounding with regard to common forecast problems.

Estimated time to complete: 6-8 h

Description:
This is part of the Physical Processes Professional Competency Unit of the Forecasting Low-Altitude Clouds and Fog for Aviation Operations Professional Development Series. West Coast Fog discusses the climatology, physical
processes, and evolution of hot spell fogs along the U.S. West Coast.

Objectives:
The goal of this training module is to help you increase your understanding of how radiation fog forms, grows, and dissipates. Such understanding, in turn, can help you more efficiently and accurately evaluate the ability of a given atmospheric environment to generate and/or maintain radiation fog.
Performance Objectives
With Regard to Climatology
Basic Level Competencies:
• Identify coastal regions worldwide where (west coast-type) fogs occur
• For each region, state the seasons of highest and lowest frequency
With Regard to the Preconditioning Environment:
Basic Level Competencies:
• Identify typical synoptic-scale patterns associated with preconditioning processes that prepare the coastal environment for fog formation
• List low-level and sea surface conditions that are typically present prior to onset of the fog formation cycle
Advanced Level Competencies:
• Sequence key processes and events that occur during the preconditioning phase
• Demonstrate an understanding of how/why the surface inversion forms as a result of hot dry offshore winds
• Describe* how/why/where coastal upwelling occurs
With Regard to Formation:
Basic Level Competencies:
• Identify typical synoptic-scale pattern transitions associated with the formation phase
• Identify the key processes and events that occur during fog formation.
Advanced Level Competencies:
• Apply rules that describe the relationships between SST, inversion base, LCL, MCL, etc.
With Regard to Growth and Maturity:
Basic Level Competencies:
Describe the continued deepening and horizontal growth of the fog
• State the typical maximum height that the inversion can reach with cloud still extending to the surface
• Describe diurnal cycles (including stratus raising/lowering)
Advanced Level Competencies:
• Demonstrate an understanding of the roles that coastal surges can play
With Regard to Fog Dissipation and/or Stratus formation:
Basic Level Competencies:
• List processes that can result in fog dissipation (advection over land, warmer water, synoptic systems, solar radiation, the start of a new cycle)
• Identify typical synoptic-scale patterns that can destroy fog regimes in MBL
• Sequence the major events that comprise the ~15-day warm season fog cycle in this region
Advanced Level Competencies:
• Describe how the fog erodes upward to form the marine stratus regime that was present prior to fog formation
• State general rule regarding relationship between sun angle and fog dissipation through insolation
• Demonstrate an understanding of how/why dissipation occurs when the MCL reaches the base of the inversion

Estimated time to complete: 1 hr

Description:
"Writing TAFs for Convective Weather" uses a case to show how special tools and techniques can be used to produce a Practically Perfect TAF (PPTAF) for convection. The unit examines how to create TAFs for different types of convection and how to effectively communicate logic and uncertainty in an aviation forecast discussion (AvnFD) or by other means. It also addresses maintaining an effective TAF weather watch and updating the TAF proactively.

Objectives:
1. Describe how general convective hazards might impact airport operations.
2. Describe how the unique characteristics of each convective type relate to creating a TAF.
3. List the strengths and weaknesses of using BUFKIT, aircraft weather data, AWIPS Time-of-Arrival (TOA)/Lead Time and Time Series tools, satellite data, climatology, and other special tools for creating a TAF for convection.
4. Explain why the PPTAF procedure needs to be revised for convection and why the use of special tools is so important for this process.
5. Produce a PPTAF for a mesoscale convective system, air mass thunderstorms, supercell thunderstorms, or microbursts
6. Effectively articulate forecast logic and uncertainty about a TAF in an Aviation Forecast Discussion (AvnFD).
7. Ensure a TAF is consistent with previous TAFs or other products issued by both local offices and national centers.
8. Be able to run an effective weather watch by identifying beforehand when a TAF update is warranted.
9. Show the ability to update proactively, rather than in a reactive fashion.
10. Identify when coordination is necessary for the TAF and with whom it should be conducted.

Estimated time to complete: 2 h

Description:
“Basic Terminal Forecast Strategies” is the first component of the Distance Learning Course 2, Producing Customer-Focused TAFs. Basic Terminal Forecast Strategies is comprised of two lessons that provide 1) an introduction to understanding aviation customers and their needs and 2) a technique to meet those needs by producing clear, concise, and consistent terminal aerodrome forecasts (TAFs).

Objectives:
1. Identify aviation customer groups and describe how they use TAFs.
2. Recognize common terminal forecast problems that adversely impact customers.
3. Analyze TAFs to determine which would be considered "good" or "poor" by customers.
4. Describe how overuse of conditional terms (e.g., TEMPO) lowers forecast verification scores and impedes effective customer decision-making.
5. Describe the relationship between aviation verification scores and customer satisfaction.
6. Create a Practically Perfect TAF (PP TAF) that meets common customer needs.

Estimated time to complete: 2 h

Description:
This module addresses issues surrounding the direct and indirect impacts of restricted ceilings and visibilities on aviation operations and also briefly examines their impacts on ground and marine transportation. The goal is improve forecaster awareness of how their forecasts of these events affect commercial and general aviation operation. This module is part of the Distance Learning Course 1: Forecasting Fog and Low Stratus.

Objectives:
• Increase awareness of the various users of ceilings and visibility forecasts and how forecasts of these conditions impact (both positively and negatively) aviation operations within each user group
    o Improve forecaster understanding of the impacts of reduced visibility and ceilings on commercial and general aviation operations
    o Improve forecaster understanding of the impact to aviation operations from forecasts (TAFs) of reduced ceiling and visibility due to fog and low stratus
    o Provide recommendations on how and when to amend TAFs to best reflect current and forecast conditions
• Increase awareness of the need to be knowledgeable about supported airport configurations
• Increase knowledge of critical thresholds and their variations from one airport to another and one user group to another

Estimated time to complete: 1 h

Description:
This is the second module in the Mesoscale Meteorology Primer series. This module starts with a forecast scenario that occurs during a winter radiation fog event in the Central Valley of California. After that, a conceptual section covers the physical processes of radiation fog through its life cycle. Operational sections addressing fog detection and forecasting conclude the module

Objectives:
At the end of the module you should be able to do the following things:

With Regard to the Preconditioning Environment:

• Identify key conditions and ingredients necessary for development of radiation fog
• Discriminate between large-scale low-level environments that are favorable and unfavorable for development of radiation fog
• Describe the sequence of key surface and boundary layer processes that prepare the low-level environment for development of radiation fog
• Demonstrate an understanding of how surface cooling dries the micro-boundary layer and prevents low-level condensation from being deposited onto the surface
• Rank various surface and surface cover types in terms of the relative speed with which low-level air in contact with them will reach saturation

With Regard to Initiation and Growth:

• Identify levels at which radiative cooling is most active at various stages of the fog initiation and growth process
• Demonstrate an understanding of the effects that various condensation nuclei types and concentrations have on fog formation
• Sequence the key processes and events that occur during formation of a layer of radiation fog
• Demonstrate an understanding of how the fog-top inversion is created by the fog itself
• Demonstrate an understanding of influences that heat flux from the surface have on a fog layer during its initiation and growth

With Regard to Maintenance Phase:

• Describe key processes that balance one another to allow a fog layer to maintain a relatively constant depth
• Identify conditions in and above a fog-top layer that support continued condensate production
• Identify conditions in and above a fog-top layer that restrict further deepening
• Demonstrate an understanding of the effects that various condensation nuclei types and concentrations have on fog maintenance
• Demonstrate an understanding of the effects that introduction of an overlying cloud layer have on a mature fog layer at the surface
• Demonstrate an understanding of influences that heat flux from the surface have on a mature fog layer
• Identify the typical level of a fog-top inversion
• Demonstrate an understanding of how the fog-top inversion is maintained by various processes at and above the top of the fog layer

With Regard to Dissipation Phase:

• Identify key processes that contribute to the dissipation of a fog layer
• Apply a droplet settling rate calculation to predict the time required for a given depth of fog layer to settle to the ground in the absence of any new condensate production
• Demonstrate an understanding of how radiative heating contributes to dissipation of a fog layer
• Demonstrate an understanding of how turbulent mixing contributes to dissipation of a fog layer
• Demonstrate an understanding of how changes in low-level winds can contribute to dissipation of a fog layer
• Demonstrate an understanding of how introduction of an overlying cloud layer can contribute to dissipation of a fog layer
With Regard to Detecting Fog:
• Identify surface observations that show atmospheric conditions conducive to radiation fog
• Identify soundings that show atmospheric conditions conducive to radiation fog
• Identify fog in satellite images
• Describe the limitations of infrared satellite images for detecting radiation fog

With Regard to Forecasting Fog:

• Describe the diurnal cycle of radiation fog occurrence
• Demonstrate and understanding of the strong seasonal dependence of radiation fog occurrence in at least two localities
• Describe which forecast products best show the atmospheric conditions conducive to radiation fog
• Describe the limitations of numerical forecast models in predicting radiation fog

Estimated time to complete: 2 h

Description:
This module provides an overview of some of the applicable TAF Amendment and Conditional Group usage rules, as presented in the latest version of the National Weather Service Instruction 10-813 on TAF directives. It also presents a methodology for TAF writing and development that will lead to an effective and user-friendly product. The focus is on the ceiling and visibility aspects of the TAF. This module is part of the Distance Learning Course 1: Forecasting Fog and Low Stratus.

Objectives:
• Develop an understanding and appreciation for how TAF construction (intelligent vs. excessive use of TEMPO and PROB groups) may impact your aviation customers
• Develop skills in writing an effective “practical” TAF that provides an improved forecast of expected flight category changes, while maintaining a customer-friendly format. Compare effective vs. poor TAF structures for a given scenario
• Develop concise TAFs with sparing use of change or conditional groups such as TEMPO and PROB, as we’ll practice in two small case exercises

Estimated time to complete: 2 h

Description:
"Writing TAFs for Convective Weather" uses a case to show how special tools and techniques can be used to produce a Practically Perfect TAF (PPTAF) for convection. The unit examines how to create TAFs for different types of convection and how to effectively communicate logic and uncertainty in an aviation forecast discussion (AvnFD) or by other means. It also addresses maintaining an effective TAF weather watch and updating the TAF proactively.

Objectives:
1. Describe how general convective hazards might impact airport operations.
2. Describe how the unique characteristics of each convective type relate to creating a TAF.
3. List the strengths and weaknesses of using BUFKIT, aircraft weather data, AWIPS Time-of-Arrival (TOA)/Lead Time and Time Series tools, satellite data, climatology, and other special tools for creating a TAF for convection.
4. Explain why the PPTAF procedure needs to be revised for convection and why the use of special tools is so important for this process.
5. Produce a PPTAF for a mesoscale convective system, air mass thunderstorms, supercell thunderstorms, or microbursts
6. Effectively articulate forecast logic and uncertainty about a TAF in an Aviation Forecast Discussion (AvnFD).
7. Ensure a TAF is consistent with previous TAFs or other products issued by both local offices and national centers.
8. Be able to run an effective weather watch by identifying beforehand when a TAF update is warranted.
9. Show the ability to update proactively, rather than in a reactive fashion.
10. Identify when coordination is necessary for the TAF and with whom it should be conducted.

Estimated time to complete: 2 h

Description:
"Writing TAFs for Winds and LLWS" is the third unit in the Distance Learning Aviation Course 2 (DLAC2) series on producing TAFs that meet the needs of the aviation community. In addition to providing information about tools for diagnosing wind and wind impacts, the module extends the Practically Perfect TAF (PPTAF) process to address airport-specific criteria. By understanding the criteria at airports for which they produce TAFs, forecasters will be better able to produce a Practically Perfect Site-Specific TAF (PPSST). The unit also examines how to effectively communicate logic and uncertainty in an aviation forecast discussion (AvnFD) and addresses maintaining an effective TAF weather watch and updating the TAF proactively.

Objectives:
* Describe the importance of accurate wind forecasts to various customers
Issue Practically Perfect TAFs that are sensitive to airport-specific criteria (i.e., PPSST—Practically Perfect Site Specific TAFs)
* Create a PPSST that meets customer needs for different airports
* Use tools, products, and data to limit uncertainty in wind and LLWS forecasts
* Use  “VRB” (Variable), “G” (Gust), and “LLWS” appropriately in a TAF
* Issue TAFs proactively and identify situations when it is best to “sit on” a TAF
* Make appropriate use of the AvnFD to express uncertainty about these phenomena
* Ensure terminal forecasts are consistent with warning, forecast, and guidance products from national aviation centers
* Demonstrate the ability to collaborate effectively when preparing a terminal forecast

Estimated time to complete: 3 h

Description:
Mountain waves form above and downwind of topographic barriers and frequently pose a serious hazard to mountain aviation because of strong-to-extreme turbulence. This foundation module describes the features of mountain waves and explores the conditions under which they form. Like other foundation modules in the Mesoscale Primer, this module starts with a forecast scenario and concludes with a final exam. Rich graphics, audio narration, and frequent interactions enhance the presentation.

Objectives:
After completing this module, the learner should be able to do the following things.

With regard to the hazards, features, and climatology of mountain waves and downslope winds:

* Identify at least 2 hazards associated with mountain wave activity
* Recall at least 3 atmospheric and topographic requirements for a mountain wave system
* Describe the major features of a mountain wave system
* Recall when and where mountain waves and downslope winds occur
* Recall the location of the following winds: Chinook, Santa Ana, Bora, and Foehn

With regard to downslope winds:

* Recall characteristics of downslope winds
* Describe why downslope winds are warm

With regard to the origin of mountain waves and downslope winds:

* Describe why air displaced over a mountain range starts to oscillate
* Recall the conditions that lead to topographically-blocked flow in terms of mountain height, wind speed, stability, and Froude number
* Describe the effects of wind shear and inversions on mountain wave activity
* Define critical level
* Discriminate between a self-induced critical level and a mean-state critical level
* Describe the different types of rotors and their associated atmospheric conditions
* Identify which type of rotor is associated with more turbulence

With regard to forecasting mountain waves and downslope winds:

* Recall the 1.6 rule-of-thumb
* Recall what NWP model resolution is required to accurately depict mountain waves
* Describe how a model's vertical coordinate system affects its ability to forecast mountain waves
* Describe how radiosondes and pilot reports (PIREPs) can help with short-range forecasting of mountain waves
* Describe how satellite imagery can be used to detect mountain wave activity with or without either daylight or clouds

Estimated time to complete: 2-3 h

Description:
"Writing TAFs for Winds and LLWS" is the third unit in the Distance Learning Aviation Course 2 (DLAC2) series on producing TAFs that meet the needs of the aviation community. In addition to providing information about tools for diagnosing wind and wind impacts, the module extends the Practically Perfect TAF (PPTAF) process to address airport-specific criteria. By understanding the criteria at airports for which they produce TAFs, forecasters will be better able to produce a Practically Perfect Site-Specific TAF (PPSST). The unit also examines how to effectively communicate logic and uncertainty in an aviation forecast discussion (AvnFD) and addresses maintaining an effective TAF weather watch and updating the TAF proactively.

Objectives:
* Describe the importance of accurate wind forecasts to various customers
Issue Practically Perfect TAFs that are sensitive to airport-specific criteria (i.e., PPSST—Practically Perfect Site Specific TAFs)
* Create a PPSST that meets customer needs for different airports
* Use tools, products, and data to limit uncertainty in wind and LLWS forecasts
* Use  “VRB” (Variable), “G” (Gust), and “LLWS” appropriately in a TAF
* Issue TAFs proactively and identify situations when it is best to “sit on” a TAF
* Make appropriate use of the AvnFD to express uncertainty about these phenomena
* Ensure terminal forecasts are consistent with warning, forecast, and guidance products from national aviation centers
* Demonstrate the ability to collaborate effectively when preparing a terminal forecast

Estimated time to complete: 3 h

Description:
This module provides an overview of some of the applicable TAF Amendment and Conditional Group usage rules, as presented in the latest version of the National Weather Service Instruction 10-813 on TAF directives. It also presents a methodology for TAF writing and development that will lead to an effective and user-friendly product. The focus is on the ceiling and visibility aspects of the TAF. This module is part of the Distance Learning Course 1: Forecasting Fog and Low Stratus.

Objectives:
• Develop an understanding and appreciation for how TAF construction (intelligent vs. excessive use of TEMPO and PROB groups) may impact your aviation customers
• Develop skills in writing an effective “practical” TAF that provides an improved forecast of expected flight category changes, while maintaining a customer-friendly format. Compare effective vs. poor TAF structures for a given scenario
• Develop concise TAFs with sparing use of change or conditional groups such as TEMPO and PROB, as we’ll practice in two small case exercises

Estimated time to complete: 2 h

Description:
"Writing TAFs for Winds and LLWS" is the third unit in the Distance Learning Aviation Course 2 (DLAC2) series on producing TAFs that meet the needs of the aviation community. In addition to providing information about tools for diagnosing wind and wind impacts, the module extends the Practically Perfect TAF (PPTAF) process to address airport-specific criteria. By understanding the criteria at airports for which they produce TAFs, forecasters will be better able to produce a Practically Perfect Site-Specific TAF (PPSST). The unit also examines how to effectively communicate logic and uncertainty in an aviation forecast discussion (AvnFD) and addresses maintaining an effective TAF weather watch and updating the TAF proactively.

Objectives:
* Describe the importance of accurate wind forecasts to various customers
Issue Practically Perfect TAFs that are sensitive to airport-specific criteria (i.e., PPSST—Practically Perfect Site Specific TAFs)
* Create a PPSST that meets customer needs for different airports
* Use tools, products, and data to limit uncertainty in wind and LLWS forecasts
* Use  “VRB” (Variable), “G” (Gust), and “LLWS” appropriately in a TAF
* Issue TAFs proactively and identify situations when it is best to “sit on” a TAF
* Make appropriate use of the AvnFD to express uncertainty about these phenomena
* Ensure terminal forecasts are consistent with warning, forecast, and guidance products from national aviation centers
* Demonstrate the ability to collaborate effectively when preparing a terminal forecast

Estimated time to complete: 3 h